rtc: spear: convert to SPDX identifier

Use SPDX-License-Identifier instead of a verbose license text.
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210707075804.337458-11-nobuhiro1.iwamatsu@toshiba.co.jp

drivers/rtc/rtc-spear.c

+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * drivers/rtc/rtc-spear.c
  *
  * Copyright (C) 2010 ST Microelectronics
  * Rajeev Kumar<rajeev-dlh.kumar@st.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/bcd.h>