ARM: dts: imx: Switch to SPDX identifier

Adopt the SPDX license identifier headers to ease license compliance
management.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx35.dtsi

@@ -1,12 +1,8 @@
-/*
- * Copyright 2012 Steffen Trumtrar, Pengutronix
- *
- * based on imx27.dtsi
- *
- * 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.
- */
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright 2012 Steffen Trumtrar, Pengutronix
+//
+// based on imx27.dtsi
 
 #include "imx35-pinfunc.h"