rtc: pcap: convert to SPDX identifier

Use SPDX-License-Identifier instead of a verbose license text.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-pcap.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  *  pcap rtc code for Motorola EZX phones
  *
@@ -5,11 +6,6 @@
  *  Copyright (c) 2009 Daniel Ribeiro <drwyrm@gmail.com>
  *
  *  Based on Motorola's rtc.c Copyright (c) 2003-2005 Motorola
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License version 2 as
- *  published by the Free Software Foundation.
- *
  */
 
 #include <linux/kernel.h>