power: supply: s3c_adc_battery: add SPDX license identifier

Add SPDX license identifier and replace license boilerplate.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/s3c_adc_battery.c

-/*
- *	iPAQ h1930/h1940/rx1950 battery controller driver
- *	Copyright (c) Vasily Khoruzhick
- *	Based on h1940_battery.c by Arnaud Patard
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file COPYING in the main directory of this archive for
- * more details.
- *
- */
+// SPDX-License-Identifier: GPL-2.0
+//
+// iPAQ h1930/h1940/rx1950 battery controller driver
+// Copyright (c) Vasily Khoruzhick
+// Based on h1940_battery.c by Arnaud Patard
 
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>