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

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: Bjorn Andersson <andersson@kernel.org>