ARM: tegra: acer-a500: Rename avdd to vdda of touchscreen node

Rename avdd supply to vdda of the touchscreen node. The old supply name
was incorrect.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra20-acer-a500-picasso.dts

@@ -448,7 +448,7 @@ touchscreen@4c {
 
 			reset-gpios = <&gpio TEGRA_GPIO(Q, 7) GPIO_ACTIVE_LOW>;
 
-			avdd-supply = <&vdd_3v3_sys>;
+			vdda-supply = <&vdd_3v3_sys>;
 			vdd-supply  = <&vdd_3v3_sys>;
 		};