of: Use SPDX license tag for DT files

Convert remaining DT files to use SPDX-License-Identifier tags.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index b7cf84b..d67dbda 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -1,15 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  *    Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
  *			 <benh@kernel.crashing.org>
  *    and		 Arnd Bergmann, IBM Corp.
  *    Merged from powerpc/kernel/of_platform.c and
  *    sparc{,64}/kernel/of_device.c by Stephen Rothwell
- *
- *  This program is free software; you can redistribute it and/or
- *  modify it under the terms of the GNU General Public License
- *  as published by the Free Software Foundation; either version
- *  2 of the License, or (at your option) any later version.
- *
  */
 
 #define pr_fmt(fmt)	"OF: " fmt