ARM: shmobile: koelsch: Enable DU device in DT

Specify the DU output topology, enable the DU device and configure the
related pins.

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

arch/arm/boot/dts/r8a7791-koelsch.dts

@@ -211,14 +211,24 @@
 	};
 };
 
+&du {
+	pinctrl-0 = <&du_pins>;
+	pinctrl-names = "default";
+	status = "okay";
+
+	ports {
+		port@1 {
+			lvds_connector: endpoint {
+			};
+		};
+	};
+};
+
 &extal_clk {
 	clock-frequency = <20000000>;
 };
 
 &pfc {
-	pinctrl-0 = <&du_pins>;
-	pinctrl-names = "default";
-
 	i2c2_pins: i2c2 {
 		renesas,groups = "i2c2";
 		renesas,function = "i2c2";