ARM: dts: TS-4800: add touchscreen support

This commit enables the touchscreen on TS-4800, using the ts4800-ts
driver.

Signed-off-by: Damien Riegel <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm/boot/dts/imx51-ts4800.dts

···
 				syscon = <&syscon 0xe>;
 			};
 		};
+
+		touchscreen {
+			compatible = "technologic,ts4800-ts";
+			reg = <0x12000 0x1000>;
+			syscon = <&syscon 0x10 6>;
+		};
 	};
 };