ARM: dts: stm32: enable Vivante GPU support on stm32mp157c-ed1 board

Enable Vivante GPU driver for stm32mp157c-ed1 board.
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157c-ed1.dts

@@ -23,6 +23,17 @@ memory@c0000000 {
 		reg = <0xC0000000 0x40000000>;
 	};
 
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		gpu_reserved: gpu@e8000000 {
+			reg = <0xe8000000 0x8000000>;
+			no-map;
+		};
+	};
+
 	aliases {
 		serial0 = &uart4;
 	};
@@ -61,6 +72,11 @@ &dts {
 	status = "okay";
 };
 
+&gpu {
+	contiguous-area = <&gpu_reserved>;
+	status = "okay";
+};
+
 &i2c4 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&i2c4_pins_a>;