ARM: dts: rockchip: enable Mali gpu on rk3066 marsboard

The rk3066 contains a Mali400 GPU, so enable it.

There is no individual (or even controllable) supply for the GPU
on the board.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20250503201043.990933-3-heiko@sntech.de

arch/arm/boot/dts/rockchip/rk3066a-marsboard.dts

@@ -69,6 +69,10 @@
 	cpu-supply = <&vdd_arm>;
 };
 
+&gpu {
+	status = "okay";
+};
+
 &hdmi {
 	status = "okay";
 };