iio: adc: meson_saradc: update with SPDX Licence identifier

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/meson_saradc.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * Amlogic Meson Successive Approximation Register (SAR) A/D Converter
  *
  * Copyright (C) 2017 Martin Blumenstingl <martin.blumenstingl@googlemail.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/>.
  */
 
 #include <linux/bitfield.h>