gpio: wm8xxx: Cut down on boilerplate

Just use the SPDX license tag for these drivers.

Cc: patches@opensource.cirrus.com
Cc: Charles Keepax <ckeepax@opensource.cirrus.com>
Cc: Mark Brown <broonie@kernel.org>
Acked-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-wm831x.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * gpiolib support for Wolfson WM831x PMICs
  *
@@ -5,11 +6,6 @@
  *
  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  *
- *  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.
- *
  */
 
 #include <linux/kernel.h>

drivers/gpio/gpio-wm8350.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * gpiolib support for Wolfson WM835x PMICs
  *
@@ -5,11 +6,6 @@
  *
  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  *
- *  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.
- *
  */
 
 #include <linux/kernel.h>

drivers/gpio/gpio-wm8994.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * gpiolib support for Wolfson WM8994
  *
@@ -5,11 +6,6 @@
  *
  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  *
- *  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.
- *
  */
 
 #include <linux/kernel.h>