pinctrl: u300: Fix SPDX tags

Some files were missing the appropriate SPDX tags so
fixed it up.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-coh901.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * U300 GPIO module.
  *
  * Copyright (C) 2007-2012 ST-Ericsson AB
- * License terms: GNU General Public License (GPL) version 2
  * COH 901 571/3 - Used in DB3210 (U365 2.0) and DB3350 (U335 1.0)
  * Author: Linus Walleij <linus.walleij@linaro.org>
  * Author: Jonas Aaberg <jonas.aberg@stericsson.com>

drivers/pinctrl/pinctrl-u300.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * Driver for the U300 pin controller
  *