arm64: hip05-d02: Document devicetree bindings for Hisilicon Hip05-D02 Board

This patch adds documentation for the devicetree bindings used by the
DT files of Hisilicon Hip05-D02 development board.
Signed-off-by: NDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: NWei Xu <xuwei5@hisilicon.com>

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

@@ -20,6 +20,10 @@ HiKey Board
 Required root node properties:
 	- compatible = "hisilicon,hi6220-hikey", "hisilicon,hi6220";
 
+HiP05 D02 Board
+Required root node properties:
+	- compatible = "hisilicon,hip05-d02";
+
 Hisilicon system controller
 
 Required properties: