arm64: dts: Add reset dts config for Hisilicon Hi6220 SoC

Add reset controller for hi6220 hikey-board.
Signed-off-by: Chen Feng <puck.chen@hisilicon.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

arch/arm64/boot/dts/hisilicon/hi6220.dtsi

@@ -147,6 +147,7 @@ sys_ctrl: sys_ctrl@f7030000 {
 			compatible = "hisilicon,hi6220-sysctrl", "syscon";
 			reg = <0x0 0xf7030000 0x0 0x2000>;
 			#clock-cells = <1>;
+			#reset-cells = <1>;
 		};
 
 		media_ctrl: media_ctrl@f4410000 {