rtc: digicolor: convert to SPDX identifier

Use SPDX-License-Identifier instead of a verbose license text.
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-digicolor.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Real Time Clock driver for Conexant Digicolor
  *
  * Copyright (C) 2015 Paradox Innovation Ltd.
  *
  * Author: Baruch Siach <baruch@tkos.co.il>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2 of the License, or (at your
- * option) any later version.
  */
 
 #include <linux/io.h>