dt-bindings: arm: hisilicon: add bindings for hi3798cv200 SoC and Poplar board

Add bindings for HiSilicon hi3798cv200 SoC and Poplar Board.
Signed-off-by: NJiancheng Xue <xuejiancheng@hisilicon.com>
Reviewed-by: NAlex Elder <elder@linaro.org>
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NWei Xu <xuwei5@hisilicon.com>

Documentation/devicetree/bindings/arm/hisilicon/hisilicon.txt

@@ -4,6 +4,14 @@ Hi3660 SoC
 Required root node properties:
 	- compatible = "hisilicon,hi3660";
 
+Hi3798cv200 SoC
+Required root node properties:
+	- compatible = "hisilicon,hi3798cv200";
+
+Hi3798cv200 Poplar Board
+Required root node properties:
+	- compatible = "hisilicon,hi3798cv200-poplar", "hisilicon,hi3798cv200";
+
 Hi4511 Board
 Required root node properties:
 	- compatible = "hisilicon,hi3620-hi4511";