dt-bindings: gpio: meson-gxl-gpio: update with SPDX Licence identifier

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

include/dt-bindings/gpio/meson-gxl-gpio.h

+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * GPIO definitions for Amlogic Meson GXL SoCs
  *
  * Copyright (C) 2016 Endless Mobile, Inc.
  * Author: Carlo Caione <carlo@endlessm.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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef _DT_BINDINGS_MESON_GXL_GPIO_H