src/northbridge: Use SPDX for GPL-2.0-only files

Done with sed and God Lines. Only done for C-like code for now.

Change-Id: Id2cb642baa764fd69543460ba869cd822ab5acad
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40056
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
diff --git a/src/northbridge/intel/i440bx/northbridge.c b/src/northbridge/intel/i440bx/northbridge.c
index 1d0251f..eb0d3b1 100644
--- a/src/northbridge/intel/i440bx/northbridge.c
+++ b/src/northbridge/intel/i440bx/northbridge.c
@@ -1,15 +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; version 2 of the License.
- *
- * 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-only */
+/* This file is part of the coreboot project. */
 
 #include <console/console.h>
 #include <device/pci_ops.h>