arm64: dts: apple: Connect dcp and atc-phy for dp2hdmi on Macbook Pros

The type-c mux lookup requires a graph connection between dcp and
atc-phy.

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

arch/arm64/boot/dts/apple/t600x-j314-j316.dtsi

@@ -107,6 +107,19 @@
 	mux-control-names = "dp-xbar";
 	mux-index = <0>;
 	apple,dptx-phy = <3>;
+
+	ports {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		port@1 {
+			reg = <1>;
+
+			decpext0_dpout: endpoint {
+				remote-endpoint = <&atcphy3_dp>;
+			};
+		};
+	};
 };
 
 /* remove once m1n1 enables sio nodes after setup */
@@ -553,6 +566,20 @@
 	};
 };
 
+&atcphy3 {
+	ports {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		port@2 {
+			reg = <2>;
+			atcphy3_dp: endpoint {
+				remote-endpoint = <&decpext0_dpout>;
+			};
+		};
+	};
+};
+
 &aop_mbox {
        status = "okay";
 };