ARM: dts: owl: Convert to new-style SPDX license identifiers

Move the SPDX-License-Identifier lines to the top.
Signed-off-by: Andreas Färber <afaerber@suse.de>

arch/arm/boot/dts/owl-s500-cubieboard6.dts

+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
 /*
  * Cubietech CubieBoard6
  *
  * Copyright (c) 2017 Andreas Färber
- *
- * SPDX-License-Identifier: (GPL-2.0+ OR MIT)
  */
 
 /dts-v1/;

arch/arm/boot/dts/owl-s500-guitar-bb-rev-b.dts

+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
 /*
  * Copyright (c) 2016-2017 Andreas Färber
- *
- * SPDX-License-Identifier: (GPL-2.0+ OR MIT)
  */
 
 /dts-v1/;

arch/arm/boot/dts/owl-s500-guitar.dtsi

+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
 /*
  * LeMaker Guitar SoM
  *
  * Copyright (c) 2016-2017 Andreas Färber
- *
- * SPDX-License-Identifier: (GPL-2.0+ OR MIT)
  */
 
 #include "owl-s500.dtsi"

arch/arm/boot/dts/owl-s500.dtsi

+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
 /*
  * Actions Semi S500 SoC
  *
  * Copyright (c) 2016-2017 Andreas Färber
- *
- * SPDX-License-Identifier: (GPL-2.0+ OR MIT)
  */
 
 #include <dt-bindings/interrupt-controller/arm-gic.h>