arm64: dts: hi3660: Add stub clock node

Add stub clock node for hi3660 platform.
Reviewed-by: NLeo Yan <leo.yan@linaro.org>
Signed-off-by: NKaihua Zhong <zhongkaihua@huawei.com>
Signed-off-by: NLeo Yan <leo.yan@linaro.org>
Signed-off-by: NWei Xu <xuwei5@hisilicon.com>

arch/arm64/boot/dts/hisilicon/hi3660.dtsi

@@ -282,6 +282,13 @@
 			#mbox-cells = <3>;
 		};
 
+		stub_clock: stub_clock@e896b500 {
+			compatible = "hisilicon,hi3660-stub-clk";
+			reg = <0x0 0xe896b500 0x0 0x0100>;
+			#clock-cells = <1>;
+			mboxes = <&mailbox 13 3 0>;
+		};
+
 		dual_timer0: timer@fff14000 {
 			compatible = "arm,sp804", "arm,primecell";
 			reg = <0x0 0xfff14000 0x0 0x1000>;