arm64: dts: qcom: x1e80100-qcp: Enable external DP support

Now that the FSUSB42 USB switches are described, enable support for DP on
the three USB-C ports of the X1E80100 QCP. It supports up to 4 lanes, but
for now we need to limit this to 2 lanes due to limitations in the USB/DP
combo PHY driver. The same limitation also exists on other boards upstream.

Co-developed-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20241212-x1e80100-qcp-dp-v1-3-37cb362a0dfe@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm64/boot/dts/qcom/x1e80100-qcp.dts

@@ -711,6 +711,30 @@
 	status = "okay";
 };
 
+&mdss_dp0 {
+	status = "okay";
+};
+
+&mdss_dp0_out {
+	data-lanes = <0 1>;
+};
+
+&mdss_dp1 {
+	status = "okay";
+};
+
+&mdss_dp1_out {
+	data-lanes = <0 1>;
+};
+
+&mdss_dp2 {
+	status = "okay";
+};
+
+&mdss_dp2_out {
+	data-lanes = <0 1>;
+};
+
 &mdss_dp3 {
 	compatible = "qcom,x1e80100-dp";
 	/delete-property/ #sound-dai-cells;