ARM: dts: rockchip: add hym8563 rtc to Radxa Rock board

The Radxa Rock uses a hym8563 as rtc. Add the i2c device and necessary
pinconfig for the interrupt pin - labeled rtc_int in the schematics.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm/boot/dts/rk3188-radxarock.dts

@@ -80,6 +80,17 @@ &i2c1 {
 	status = "okay";
 	clock-frequency = <400000>;
 
+	rtc@51 {
+		compatible = "haoyu,hym8563";
+		reg = <0x51>;
+		interrupt-parent = <&gpio0>;
+		interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&rtc_int>;
+		#clock-cells = <0>;
+		clock-output-names = "xin32k";
+	};
+
 	act8846: act8846@5a {
 		compatible = "active-semi,act8846";
 		reg = <0x5a>;
@@ -196,6 +207,12 @@ act8846_dvs0_ctl: act8846-dvs0-ctl {
 		};
 	};
 
+	hym8563 {
+		rtc_int: rtc-int {
+			rockchip,pins = <RK_GPIO0 0 RK_FUNC_GPIO &pcfg_pull_up>;
+		};
+	};
+
 	ir-receiver {
 		ir_recv_pin: ir-recv-pin {
 			rockchip,pins = <RK_GPIO0 10 RK_FUNC_GPIO &pcfg_pull_none>;