arm64: dts: qcom: sc8280xp: Add USB-C-related DP blocks

Add the two DisplayPort controllers that are attached to QMP phys for
providing display output on USB Type-C.

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230213215619.1362566-2-quic_bjorande@quicinc.com