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/common/chip.h b/src/superio/common/chip.h
index fd618c5..1be2802 100644
--- a/src/superio/common/chip.h
+++ b/src/superio/common/chip.h
@@ -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. */
 
 #ifndef __SUPERIO_COMMON_CHIP_H__
 #define __SUPERIO_COMMON_CHIP_H__
diff --git a/src/superio/common/conf_mode.c b/src/superio/common/conf_mode.c
index 1e62285..83cf074 100644
--- a/src/superio/common/conf_mode.c
+++ b/src/superio/common/conf_mode.c
@@ -1,18 +1,5 @@
-/*
- * This file is part of the coreboot project.
- *
- * Copyright (C) 2013 Nico Huber <nico.h@gmx.de>
- * Copyright (C) 2017-2018 Eltan B.V.
- *
- * 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 <arch/io.h>
 #include <device/device.h>
diff --git a/src/superio/common/generic.c b/src/superio/common/generic.c
index 85b70df..de78199 100644
--- a/src/superio/common/generic.c
+++ b/src/superio/common/generic.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 */
+/* This file is part of the coreboot project. */
 
 #include <device/device.h>
 #include <device/pnp.h>
diff --git a/src/superio/common/ssdt.c b/src/superio/common/ssdt.c
index 541fa99..7aa24ea 100644
--- a/src/superio/common/ssdt.c
+++ b/src/superio/common/ssdt.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 */
+/* This file is part of the coreboot project. */
 
 #include <superio/common/ssdt.h>
 
diff --git a/src/superio/common/ssdt.h b/src/superio/common/ssdt.h
index 8c63742..1f99189 100644
--- a/src/superio/common/ssdt.h
+++ b/src/superio/common/ssdt.h
@@ -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 */
+/* This file is part of the coreboot project. */
 
 #ifndef __SUPERIO_COMMON_SSDT_H__
 #define __SUPERIO_COMMON_SSDT_H__