ARM: dts: bcm2835-rpi-zero: Switch to SPDX identifier

Adopt the SPDX license identifier headers to ease license compliance
management.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

arch/arm/boot/dts/bcm2835-rpi-zero-w.dts

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2017 Stefan Wahren <stefan.wahren@i2se.com>
- *
- * The code contained herein is licensed under the GNU General Public
- * License. You may obtain a copy of the GNU General Public License
- * Version 2 or later at the following locations:
- *
- * http://www.opensource.org/licenses/gpl-license.html
- * http://www.gnu.org/copyleft/gpl.html
  */
 
 /dts-v1/;

arch/arm/boot/dts/bcm2835-rpi-zero.dts

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2016 Stefan Wahren <stefan.wahren@i2se.com>
- *
- * The code contained herein is licensed under the GNU General Public
- * License. You may obtain a copy of the GNU General Public License
- * Version 2 or later at the following locations:
- *
- * http://www.opensource.org/licenses/gpl-license.html
- * http://www.gnu.org/copyleft/gpl.html
  */
 
 /dts-v1/;