src/superio: replace license boilerplate with SPDX

The authors from the header of the files are added in a previous commit.

Change-Id: Iafeaafb9689c65bd2f5de3960097ec0d4c1009e7
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38544
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/superio/winbond/w83627ehg/superio.c b/src/superio/winbond/w83627ehg/superio.c
index 35fca01..ba817be 100644
--- a/src/superio/winbond/w83627ehg/superio.c
+++ b/src/superio/winbond/w83627ehg/superio.c
@@ -1,21 +1,5 @@
-/*
- * This file is part of the coreboot project.
- *
- * Copyright (C) 2000 AG Electronics Ltd.
- * Copyright (C) 2003-2004 Linux Networx
- * Copyright (C) 2004 Tyan
- * Copyright (C) 2007 AMD
- * Written by Yinghai Lu <yinghai.lu@amd.com> for AMD.
- *
- * 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.
- */
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* This file is part of the coreboot project. */
 
 #include <device/device.h>
 #include <device/pnp.h>