rtc: ds1374: 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/20210707075804.337458-3-nobuhiro1.iwamatsu@toshiba.co.jp

drivers/rtc/rtc-ds1374.c

+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * RTC client/driver for the Maxim/Dallas DS1374 Real-Time Clock over I2C
  *
@@ -6,11 +7,7 @@
  *
  * Copyright (C) 2014 Rose Technology
  * Copyright (C) 2006-2007 Freescale Semiconductor
- *
- * 2005 (c) MontaVista Software, Inc. 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.
+ * Copyright (c) 2005 MontaVista Software, Inc.
  */
 /*
  * It would be more efficient to use i2c msgs/i2c_transfer directly but, as