util: Add SPDX license headers to Makefiles

Signed-off-by: Martin Roth <gaumless@gmail.com>
Change-Id: I7cf35132df0bc23f7b6f78014ddd72d58ea2ab8a
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68983
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>

util/msrtool/Makefile.in

@@ -1,15 +1,6 @@
+## SPDX-License-Identifier: GPL-2.0-only
 # Makefile for msrtool
 #
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License version 2 as
-# published by the Free Software Foundation.
-#
-# 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.
-#
 
 PROGRAM = msrtool