pinctrl: sh-pfc: Convert to SPDX identifiers

This patch updates license to use SPDX-License-Identifier
instead of verbose license text.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

drivers/pinctrl/sh-pfc/gpio.c

@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * SuperH Pin Function Controller GPIO driver.
  *
  * Copyright (C) 2008 Magnus Damm
  * Copyright (C) 2009 - 2012 Paul Mundt
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
  */
 
 #include <linux/device.h>