treewide: replace GPLv2 long form headers with SPDX header

This replaces GPLv2-or-later and GPLv2-only long form text with the
short SPDX identifiers.

Commands used:
perl -i -p0e 's|/\*[*\n\t ]*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[;,].*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.*even.*the.*implied.*warranty.*of.*MERCHANTABILITY.*or.*FITNESS.*FOR.*A.*PARTICULAR.*PURPOSE..*.*See.*the.*GNU.*General.*Public.*License for more details.[\n\t ]*\*/|/* SPDX-License-Identifier: GPL-2.0-or-later */|s' $(cat filelist)

perl -i -p0e 's|/\*[*\n\t ]*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[;,].*version.*2.+This.*program.*is.*distributed.*in.*the.*hope.*that.*it.*will.*be.*useful,.*but.*;.*without.*even.*the.*implied.*warranty.*of.*MERCHANTABILITY.*or.*FITNESS.*FOR.*A.*PARTICULAR.*PURPOSE..*.*See.*the.*GNU.*General.*Public.*License for more details.[\n\t ]*\*/|/* SPDX-License-Identifier: GPL-2.0-only */|s' $(cat filelist)

perl -i -p0e 's|/\*[*\n\t ]*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.*even.*the.*implied.*warranty.*of.*MERCHANTABILITY.*or.*FITNESS.*FOR.*A.*PARTICULAR.*PURPOSE..*.*See.*the.*GNU.*General.*Public.*License for more details.[\n\t ]*\*/|/* SPDX-License-Identifier: GPL-2.0-only */|s' $(cat filelist)

perl -i -p0e 's|/\*[*\n\t ]*This software is licensed 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.*even.*the.*implied.*warranty.*of.*MERCHANTABILITY.*or.*FITNESS.*FOR.*A.*PARTICULAR.*PURPOSE..*.*See.*the.*GNU.*General.*Public.*License for more details.[\n\t ]*\*/|/* SPDX-License-Identifier: GPL-2.0-only */|s' $(cat filelist)

Change-Id: I7a746088a35633c11fc7ebe86006e96458a1abf8
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41066
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
diff --git a/src/northbridge/intel/x4x/raminit_ddr23.c b/src/northbridge/intel/x4x/raminit_ddr23.c
index 81e6395..e0ce340 100644
--- a/src/northbridge/intel/x4x/raminit_ddr23.c
+++ b/src/northbridge/intel/x4x/raminit_ddr23.c
@@ -1,16 +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 */
 
 #include <assert.h>
 #include <stdint.h>