gpio: wm8xxx: Cut down on boilerplate

Just use the SPDX license tag for these drivers.

Cc: [e-mail]
Cc: Charles Keepax <[e-mail]>
Cc: Mark Brown <[e-mail]>
Acked-by: Richard Fitzgerald <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpio-wm831x.c

···
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * gpiolib support for Wolfson WM831x PMICs
  *
  * Copyright 2009 Wolfson Microelectronics PLC.
  *
  * Author: Mark Brown <[e-mail]>
- *
- *  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.
  *
  */
 

drivers/gpio/gpio-wm8350.c

···
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * gpiolib support for Wolfson WM835x PMICs
  *
  * Copyright 2009 Wolfson Microelectronics PLC.
  *
  * Author: Mark Brown <[e-mail]>
- *
- *  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.
  *
  */
 

drivers/gpio/gpio-wm8994.c

···
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * gpiolib support for Wolfson WM8994
  *
  * Copyright 2009 Wolfson Microelectronics PLC.
  *
  * Author: Mark Brown <[e-mail]>
- *
- *  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.
  *
  */