ARM: dts: sun6i: add rtc device node

Now that we have a driver for sun6i's rtc hardware, add a device node
for it so we can use it.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

arch/arm/boot/dts/sun6i-a31.dtsi

@@ -779,6 +779,12 @@ gic: interrupt-controller@01c81000 {
 			interrupts = <1 9 0xf04>;
 		};
 
+		rtc: rtc@01f00000 {
+			compatible = "allwinner,sun6i-a31-rtc";
+			reg = <0x01f00000 0x54>;
+			interrupts = <0 40 4>, <0 41 4>;
+		};
+
 		nmi_intc: interrupt-controller@01f00c0c {
 			compatible = "allwinner,sun6i-a31-sc-nmi";
 			interrupt-controller;