ARM: tegra: add touchpad to Venice2 DT

Venice2 contains an Atmel MXT touchpad. Add an I2C node for it to DT.
The Linux driver doesn't quite work on this platform yet, but adding
the DT node causes no issues, and will allow the device to work once
the driver is fixed.
Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/boot/dts/tegra124-venice2.dts

@@ -606,6 +606,14 @@ acodec: audio-codec@10 {
 	i2c@0,7000c400 {
 		status = "okay";
 		clock-frequency = <100000>;
+
+		trackpad@4b {
+			compatible = "atmel,maxtouch";
+			reg = <0x4b>;
+			interrupt-parent = <&gpio>;
+			interrupts = <TEGRA_GPIO(W, 3) IRQ_TYPE_LEVEL_LOW>;
+			linux,gpio-keymap = <0 0 0 BTN_LEFT>;
+		};
 	};
 
 	i2c@0,7000c500 {