rtc: mv: convert to SPDX identifier

Use SPDX-License-Identifier instead of a verbose license text.

Reviewed-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-mv.c

@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Driver for the RTC in Marvell SoCs.
- *
- * This file is licensed under the terms of the GNU General Public
- * License version 2.  This program is licensed "as is" without any
- * warranty of any kind, whether express or implied.
  */
 
 #include <linux/init.h>