i2c: use SPDX identifier for Renesas drivers

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-riic.c

@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Renesas RIIC driver
  *
  * Copyright (C) 2013 Wolfram Sang <wsa@sang-engineering.com>
  * Copyright (C) 2013 Renesas Solutions Corp.
- *
- * 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.
  */
 
 /*