gpio: bd9571mwv: Use the SPDX license identifier

Use the SPDX license identifier instead of a local description.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/gpio/gpio-bd9571mwv.c

+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * ROHM BD9571MWV-M GPIO driver
  *
  * Copyright (C) 2017 Marek Vasut <marek.vasut+renesas@gmail.com>
  *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed "as is" WITHOUT ANY WARRANTY of any
- * kind, whether expressed or implied; without even the implied warranty
- * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License version 2 for more details.
- *
  * Based on the TPS65086 driver
  *
  * NOTE: Interrupts are not supported yet.