ARM: dts: exynos: Add GPU/Mali 400 node to Exynos3250

Add nodes for GPU (Mali 400) to Exynos3250.  This is still limited and
not tested:
1. No dynamic voltage and frequency scaling,
2. Not sure what to do with CLK_G3D clock responsible for gating entire
   IP block (it is now being disabled as unused).

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

arch/arm/boot/dts/exynos3250-monk.dts

@@ -172,6 +172,11 @@
 	status = "okay";
 };
 
+&gpu {
+	mali-supply = <&buck3_reg>;
+	status = "okay";
+};
+
 &hsotg {
 	vusb_d-supply = <&ldo15_reg>;
 	vusb_a-supply = <&ldo12_reg>;