arm: dts: am335x sk: add touchscreen support

Add missing nodes for the touchscreen available on AM335x EVM SK.
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

arch/arm/boot/dts/am335x-evmsk.dts

@@ -419,3 +419,13 @@ &cpsw_emac1 {
 	phy_id = <&davinci_mdio>, <1>;
 	phy-mode = "rgmii-txid";
 };
+
+&tscadc {
+	status = "okay";
+	tsc {
+		ti,wires = <4>;
+		ti,x-plate-resistance = <200>;
+		ti,coordinate-readouts = <5>;
+		ti,wire-config = <0x00 0x11 0x22 0x33>;
+	};
+};