arm64: dts: renesas: r8a77965-salvator-x: Enable DU external clocks and HDMI

The DU1 external dot clock is provided by the fixed frequency clock
generator X21, while the DU0 and DU3 clocks are provided by the
programmable Versaclock5 clock generator.

Enable the clocks, and the HDMI encoder for the M3-N Salvator-X board
and hook it up to the HDMI connector.

Based on patches from Takeshi Kihara <takeshi.kihara.df@renesas.com>
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-salvator-x.dts

@@ -19,3 +19,31 @@ memory@48000000 {
 		reg = <0x0 0x48000000 0x0 0x78000000>;
 	};
 };
+
+&du {
+	clocks = <&cpg CPG_MOD 724>,
+		 <&cpg CPG_MOD 723>,
+		 <&cpg CPG_MOD 721>,
+		 <&versaclock5 1>,
+		 <&x21_clk>,
+		 <&versaclock5 2>;
+	clock-names = "du.0", "du.1", "du.3",
+		      "dclkin.0", "dclkin.1", "dclkin.3";
+};
+
+&hdmi0 {
+	status = "okay";
+
+	ports {
+		port@1 {
+			reg = <1>;
+			rcar_dw_hdmi0_out: endpoint {
+				remote-endpoint = <&hdmi0_con>;
+			};
+		};
+	};
+};
+
+&hdmi0_con {
+	remote-endpoint = <&rcar_dw_hdmi0_out>;
+};