arm64: dts: rockchip: add rock960 board support

rock960 board is the first rockchip SoC based 96board, so we should
support this board in our SDK. grab this dts from below url.

the initial author is Jack Ma <jack@vamrs.com>
https://raw.githubusercontent.com/96rocks/kernel/rock960-4.4-dev/
arch/arm64/boot/dts/rockchip/rock960-model-ab-linux.dts

Change-Id: I823d7a4b129716c1df4d0a6795118abfaf7120f0
Signed-offf-by: Jack Ma <jack@vamrs.com>
Signed-off-by: Eddie Cai <eddie.cai.linux@gmail.com>

Documentation/devicetree/bindings/arm/rockchip.txt

@@ -115,6 +115,10 @@ Rockchip platforms device tree bindings
     Required root node properties:
       - compatible = "rockchip,rk3399-evb", "rockchip,rk3399";
 
+- Rockchip RK3399 Rock960 version ab board:
+    Required root node properties:
+      - compatible = "rockchip,rock960", "rockchip,rk3399";
+
 - Rockchip RK3326 f863 board:
     Required root node properties:
       - compatible = "rockchip,rk3326-863-lp3-v10", "rockchip,rk3326";

arch/arm64/boot/dts/rockchip/Makefile

@@ -64,6 +64,7 @@ dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-gru-kevin-r0.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-gru-kevin-r1.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-mid-818-android-6.0.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-mid-818-android.dtb
+dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-rock960-ab.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-rockpro64.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-rv1-android.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-sapphire-excavator-box-android-6.0.dtb