arm64: dts: renesas: rz-smarc-du-adv7513: Simplify DU port configuration

The SoC dtsi already defines the du node with its ports hierarchy,
including the du_out_rgb endpoint node under port@0.  There is no need
to redefine the entire ports/port@0 structure in the board-level dtsi.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260420132211.1350656-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: prabhakarlad

arch/arm64/boot/dts/renesas/rz-smarc-du-adv7513.dtsi

@@ -24,19 +24,10 @@
 	pinctrl-names = "default";
 
 	status = "okay";
+};
 
-	ports {
-		#address-cells = <1>;
-		#size-cells = <0>;
-
-		port@0 {
-			reg = <0>;
-
-			du_out_rgb: endpoint {
-				remote-endpoint = <&adv7513_in>;
-			};
-		};
-	};
+&du_out_rgb {
+	remote-endpoint = <&adv7513_in>;
 };
 
 &ADV7513_PARENT_I2C {