rtc: moxart: Convert to SPDX identifier

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

CC: Alessandro Zummo <[e-mail]>
CC: Alexandre Belloni <[e-mail]>
CC: Jonas Jensen <[e-mail]>
Signed-off-by: Nobuhiro Iwamatsu <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexandre Belloni <[e-mail]>

drivers/rtc/rtc-moxart.c

···
+// SPDX-License-Identifier: GPL-2.0
 /*
  * MOXA ART RTC driver.
  *
···
  *
  * 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>