treewide: Convert more license headers to SPDX style

Change-Id: Ia3de79c7d71049da00ed108829eac6cb49ff3ed6
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41205
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/security/intel/stm/StmPlatformResource.c b/src/security/intel/stm/StmPlatformResource.c
index 6fef515..08b0bce 100644
--- a/src/security/intel/stm/StmPlatformResource.c
+++ b/src/security/intel/stm/StmPlatformResource.c
@@ -1,16 +1,4 @@
-/* @file
- * STM platform SMM resource
- *
- * Copyright (c) 2015, Intel Corporation. All rights reserved.
- * This program and the accompanying materials are licensed and made
- * available under the terms and conditions of the BSD License which
- * accompanies this distribution.  The full text of the license may be found
- * at http://opensource.org/licenses/bsd-license.php.
- *
- * THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
- * WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR
- * IMPLIED.
- */
+/* SPDX-License-Identifier: BSD-2-Clause */
 
 #include <stdint.h>
 #include <security/intel/stm/StmApi.h>