rtc: moxart: Convert to SPDX identifier

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

CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Alexandre Belloni <alexandre.belloni@bootlin.com>
CC: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Link: https://lore.kernel.org/r/20191218082836.3309808-1-iwamatsu@nigauri.orgSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-moxart.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * MOXA ART RTC driver.
  *
@@ -7,10 +8,6 @@
  *
  * Based on code from
  * Moxa Technology Co., Ltd. <www.moxa.com>
- *
- * 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>