br-ext: Rename OP-TEE packages with _ext suffix

Rename OP-TEE packages in br-ext with a _ext suffix so that
they do not conflict with the OP-TEE packages from Buildroot.

This change essentially renames Buildroot configuration switches
BR2_OPTEE_* to BR2_OPTEE_*_EXT_* without changing the current build
process.

This change is needed for OP-TEE build environment to synchronize with
Buildroot GIT version [1] or later in the Buildroot integration tree.
[1] points where OP-TEE packages were introduced in Buildroot,
right after 2019.02 is released. This was tested with all Buildroot
release tags from 2018.11 to 2020.02, and recent 2020.05-rc1.

Link: [1] https://git.buildroot.net/buildroot/commit/?id=da49312af9e0c3e7f6df50e7d6f77e1fa2921b7a
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/br-ext/package/optee_test_ext/Config.in b/br-ext/package/optee_test_ext/Config.in
new file mode 100644
index 0000000..47bc8ca
--- /dev/null
+++ b/br-ext/package/optee_test_ext/Config.in
@@ -0,0 +1,27 @@
+config BR2_PACKAGE_OPTEE_TEST_EXT
+	bool "optee_test"
+	select BR2_PACKAGE_OPTEE_CLIENT_EXT
+	help
+	  http://github.org/OP-TEE/optee_test
+
+if BR2_PACKAGE_OPTEE_TEST_EXT
+
+config BR2_PACKAGE_OPTEE_TEST_EXT_SITE
+	string "OP-TEE test path"
+	default ""
+	help
+	  The path to the source directory of OP-TEE test
+
+config BR2_PACKAGE_OPTEE_TEST_EXT_SDK
+	string "OPTEE SDK path"
+	default ""
+	help
+	  some help
+
+config BR2_PACKAGE_OPTEE_TEST_EXT_CROSS_COMPILE
+	string "OPTEE cross compiler"
+	default ""
+	help
+	  some help
+
+endif