ARM: dts: rockchip: enable gpu on rk3188-radxarock

Enable the gpu node on that board.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm/boot/dts/rk3188-radxarock.dts

@@ -176,6 +176,10 @@ &cpu0 {
 	cpu0-supply = <&vdd_arm>;
 };
 
+&gpu {
+	status = "okay";
+};
+
 &i2c1 {
 	status = "okay";
 	clock-frequency = <400000>;