ARM: dts: sun6i: Add resistive touchscreen controller node to dtsi

Now that we support the sun6i variant of the touchscreen controller,
add the device node to the dtsi so we can use it.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

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

@@ -640,6 +640,13 @@
 			reg = <0x01c20ca0 0x20>;
 		};
 
+		rtp: rtp@01c25000 {
+			compatible = "allwinner,sun6i-a31-ts";
+			reg = <0x01c25000 0x100>;
+			interrupts = <GIC_SPI 28 IRQ_TYPE_LEVEL_HIGH>;
+			#thermal-sensor-cells = <0>;
+		};
+
 		uart0: serial@01c28000 {
 			compatible = "snps,dw-apb-uart";
 			reg = <0x01c28000 0x400>;