Update copyright notices to use Linux Foundation guidance

As a result, the copyright of contributors other than Arm is now
acknowledged, and the years of publishing are no longer tracked in the
source files.

Also remove the now-redundant lines declaring that the files are part of
MbedTLS.

This commit was generated using the following script:

# ========================
#!/bin/sh

# Find files
find '(' -path './.git' -o -path './3rdparty' ')' -prune -o -type f -print | xargs sed -bi '

# Replace copyright attribution line
s/Copyright.*Arm.*/Copyright The Mbed TLS Contributors/I

# Remove redundant declaration and the preceding line
$!N
/This file is part of Mbed TLS/Id
P
D
'
# ========================

Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
diff --git a/programs/test/benchmark.c b/programs/test/benchmark.c
index 0c04cd8..251cbb6 100644
--- a/programs/test/benchmark.c
+++ b/programs/test/benchmark.c
@@ -1,7 +1,7 @@
 /*
  *  Benchmark demonstration program
  *
- *  Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
+ *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -15,8 +15,6 @@
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
- *
- *  This file is part of mbed TLS (https://tls.mbed.org)
  */
 
 #if !defined(MBEDTLS_CONFIG_FILE)
diff --git a/programs/test/cmake_subproject/cmake_subproject.c b/programs/test/cmake_subproject/cmake_subproject.c
index ca899bc..6d81830 100644
--- a/programs/test/cmake_subproject/cmake_subproject.c
+++ b/programs/test/cmake_subproject/cmake_subproject.c
@@ -2,7 +2,7 @@
  *  Simple program to test that CMake builds with Mbed TLS as a subdirectory
  *  work correctly.
  *
- *  Copyright (C) 2006-2019, ARM Limited, All Rights Reserved
+ *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -16,8 +16,6 @@
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
- *
- *  This file is part of mbed TLS (https://tls.mbed.org)
  */
 
 #if !defined(MBEDTLS_CONFIG_FILE)
diff --git a/programs/test/cpp_dummy_build.cpp b/programs/test/cpp_dummy_build.cpp
index 9cd5090..09c5273 100644
--- a/programs/test/cpp_dummy_build.cpp
+++ b/programs/test/cpp_dummy_build.cpp
@@ -2,7 +2,7 @@
  *  This program is a dummy C++ program to ensure Mbed TLS library header files
  *  can be included and built with a C++ compiler.
  *
- *  Copyright (C) 2018, ARM Limited, All Rights Reserved
+ *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -16,8 +16,6 @@
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
- *
- *  This file is part of mbed TLS (https://tls.mbed.org)
  */
 
 #if !defined(MBEDTLS_CONFIG_FILE)
diff --git a/programs/test/query_compile_time_config.c b/programs/test/query_compile_time_config.c
index 17becf2..abe8f76 100644
--- a/programs/test/query_compile_time_config.c
+++ b/programs/test/query_compile_time_config.c
@@ -1,7 +1,7 @@
 /*
  *  Query the Mbed TLS compile time configuration
  *
- *  Copyright (C) 2018, Arm Limited, All Rights Reserved
+ *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -15,8 +15,6 @@
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
- *
- *  This file is part of Mbed TLS (https://tls.mbed.org)
  */
 
 #if !defined(MBEDTLS_CONFIG_FILE)
diff --git a/programs/test/query_config.c b/programs/test/query_config.c
index 98b065b..e20a65e 100644
--- a/programs/test/query_config.c
+++ b/programs/test/query_config.c
@@ -1,7 +1,7 @@
 /*
  *  Query Mbed TLS compile time configurations from config.h
  *
- *  Copyright (C) 2018, Arm Limited, All Rights Reserved
+ *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -15,8 +15,6 @@
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
- *
- *  This file is part of Mbed TLS (https://tls.mbed.org)
  */
 
 #if !defined(MBEDTLS_CONFIG_FILE)
diff --git a/programs/test/selftest.c b/programs/test/selftest.c
index 3fa05f3..2aa379b 100644
--- a/programs/test/selftest.c
+++ b/programs/test/selftest.c
@@ -1,7 +1,7 @@
 /*
  *  Self-test demonstration program
  *
- *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -15,8 +15,6 @@
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
- *
- *  This file is part of mbed TLS (https://tls.mbed.org)
  */
 
 #if !defined(MBEDTLS_CONFIG_FILE)
diff --git a/programs/test/udp_proxy.c b/programs/test/udp_proxy.c
index 94bae43..0b1bfd7 100644
--- a/programs/test/udp_proxy.c
+++ b/programs/test/udp_proxy.c
@@ -1,7 +1,7 @@
 /*
  *  UDP proxy: emulate an unreliable UDP connexion for DTLS testing
  *
- *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -15,8 +15,6 @@
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
- *
- *  This file is part of mbed TLS (https://tls.mbed.org)
  */
 
 /*
diff --git a/programs/test/udp_proxy_wrapper.sh b/programs/test/udp_proxy_wrapper.sh
index cfc269a..27de013 100755
--- a/programs/test/udp_proxy_wrapper.sh
+++ b/programs/test/udp_proxy_wrapper.sh
@@ -2,7 +2,7 @@
 # -*-sh-basic-offset: 4-*-
 # Usage: udp_proxy_wrapper.sh [PROXY_PARAM...] -- [SERVER_PARAM...]
 #
-# Copyright (C) 2017, Arm Limited, All Rights Reserved
+# Copyright The Mbed TLS Contributors
 # SPDX-License-Identifier: Apache-2.0
 #
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -16,8 +16,6 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-#
-# This file is part of Mbed TLS (https://tls.mbed.org)
 
 set -u
 
diff --git a/programs/test/zeroize.c b/programs/test/zeroize.c
index e61b470..5e6b58e 100644
--- a/programs/test/zeroize.c
+++ b/programs/test/zeroize.c
@@ -9,7 +9,7 @@
  * facilities are then used to manually inspect the memory and verify that the
  * call to mbedtls_platform_zeroize() was not eliminated.
  *
- *  Copyright (C) 2018, Arm Limited, All Rights Reserved
+ *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -23,8 +23,6 @@
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
- *
- *  This file is part of mbed TLS (https://tls.mbed.org)
  */
 
 #if !defined(MBEDTLS_CONFIG_FILE)