Remove new additions of "this file is part of" lines

Change-Id: I6c69dcad82ee217ed4760dea1792dd1a6612cd8b
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41606
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

tests/commonlib/Makefile.inc

@@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-# This file is part of the coreboot project.
 
 tests-y += region-test
 

tests/commonlib/region-test.c

@@ -1,5 +1,4 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
-/* This file is part of the coreboot project. */
 
 #include <commonlib/region.h>
 #include <string.h>

tests/include/tests/test.h

@@ -1,5 +1,4 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
-/* This file is part of the coreboot project. */
 
 #ifndef _TESTS_TEST_H
 #define _TESTS_TEST_H