gpio: tps65xxx: Use SPDX license tag

I'm tired of boilerplate, use the SPDX tag.

Acked-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-tps65910.c b/drivers/gpio/gpio-tps65910.c
index 55c745b..0c785b0 100644
--- a/drivers/gpio/gpio-tps65910.c
+++ b/drivers/gpio/gpio-tps65910.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * TI TPS6591x GPIO driver
  *
@@ -5,12 +6,6 @@
  *
  * Author: Graeme Gregory <gg@slimlogic.co.uk>
  * Author: Jorge Eduardo Candelaria <jedu@slimlogic.co.uk>
- *
- *  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>