ARM: dts: stm32: enable Vivante GPU support on stm32mp157a-dk1 board

Enable Vivante GPU driver for stm32mp157a-dk1 and dk2 boards.
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157a-dk1.dts

@@ -28,6 +28,17 @@ memory@c0000000 {
 		reg = <0xc0000000 0x20000000>;
 	};
 
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		gpu_reserved: gpu@d4000000 {
+			reg = <0xd4000000 0x4000000>;
+			no-map;
+		};
+	};
+
 	led {
 		compatible = "gpio-leds";
 		blue {
@@ -65,6 +76,10 @@ phy0: ethernet-phy@0 {
 	};
 };
 
+&gpu {
+	contiguous-area = <&gpu_reserved>;
+	status = "okay";
+};
 
 &i2c4 {
 	pinctrl-names = "default";