arm64: dts: renesas: r8a77965: Populate the DU instance placeholder

The DU entity node has been previously added but only as a placeholder.
Populate the node with the properties to use the device.
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a77965.dtsi

@@ -1106,9 +1106,19 @@ ports {
 		};
 
 		du: display@feb00000 {
-			reg = <0 0xfeb00000 0 0x80000>,
-			      <0 0xfeb90000 0 0x14>;
-			/* placeholder */
+			compatible = "renesas,du-r8a77965";
+			reg = <0 0xfeb00000 0 0x80000>;
+			reg-names = "du";
+			interrupts = <GIC_SPI 256 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 268 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 270 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&cpg CPG_MOD 724>,
+				 <&cpg CPG_MOD 723>,
+				 <&cpg CPG_MOD 721>;
+			clock-names = "du.0", "du.1", "du.3";
+			status = "disabled";
+
+			vsps = <&vspd0 0 &vspd1 0 &vspd0 1>;
 
 			ports {
 				#address-cells = <1>;