Fix the license header of hkdf
Change the license header of `hkdf.h` to a format the that script
`apache_to_gpl.pl` knows how to parse.
diff --git a/include/mbedtls/hkdf.h b/include/mbedtls/hkdf.h
index 40ee64e..713c3a5 100644
--- a/include/mbedtls/hkdf.h
+++ b/include/mbedtls/hkdf.h
@@ -7,22 +7,22 @@
* specified by RFC 5869.
*/
/*
- * Copyright (C) 2016-2018, ARM Limited, All Rights Reserved
- * SPDX-License-Identifier: Apache-2.0
+ * Copyright (C) 2018-2019, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
*
- * Licensed under the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
*
- * http://www.apache.org/licenses/LICENSE-2.0
+ * http://www.apache.org/licenses/LICENSE-2.0
*
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * 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)
+ * This file is part of mbed TLS (https://tls.mbed.org)
*/
#ifndef MBEDTLS_HKDF_H
#define MBEDTLS_HKDF_H