arm64: dts: hi3798cv200: fix malformed SPDX license identifier

It fixes malformed SPDX license identifier in Hi3798CV200 and Poplar
DTS, accroding to Documentation/process/license-rules.rst.
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>

arch/arm64/boot/dts/hisilicon/hi3798cv200-poplar.dts

+// SPDX-License-Identifier: GPL-2.0
 /*
  * DTS File for HiSilicon Poplar Development Board
  *
  * Copyright (c) 2016-2017 HiSilicon Technologies Co., Ltd.
- *
- * Released under the GPLv2 only.
- * SPDX-License-Identifier: GPL-2.0
  */
 
 /dts-v1/;

arch/arm64/boot/dts/hisilicon/hi3798cv200.dtsi

+// SPDX-License-Identifier: GPL-2.0
 /*
  * DTS File for HiSilicon Hi3798cv200 SoC.
  *
  * Copyright (c) 2016-2017 HiSilicon Technologies Co., Ltd.
- *
- * Released under the GPLv2 only.
- * SPDX-License-Identifier: GPL-2.0
  */
 
 #include <dt-bindings/clock/histb-clock.h>