arm64: dts: renesas: ulcb: Enable display output

The DU is already wired up to the HDMI encoder, all we need to do is
enable it.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

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

@@ -157,6 +157,10 @@
 	};
 };
 
+&du {
+	status = "okay";
+};
+
 &ehci1 {
 	status = "okay";
 };