src/mainboard: Replace GPLv2 long form headers with SPDX header

Change-Id: I64d9468682a4aae3084b17b8724d035f17d01dff
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41187
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/src/mainboard/asrock/h81m-hds/Kconfig b/src/mainboard/asrock/h81m-hds/Kconfig
index dd26464..b0ae030 100644
--- a/src/mainboard/asrock/h81m-hds/Kconfig
+++ b/src/mainboard/asrock/h81m-hds/Kconfig
@@ -1,17 +1,5 @@
-##
 ## This file is part of the coreboot project.
-##
-##
-## This program is free software: you can redistribute it and/or modify
-## it under the terms of the GNU General Public License as published by
-## the Free Software Foundation, either version 2 of the License, or
-## (at your option) any later version.
-##
-## This program is distributed in the hope that it will be useful,
-## but WITHOUT ANY WARRANTY; without even the implied warranty of
-## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-## GNU General Public License for more details.
-##
+## SPDX-License-Identifier: GPL-2.0-or-later
 
 if BOARD_ASROCK_H81M_HDS