arm64: dts: qcom: sc8280xp: Define some of the display blocks

Define the display clock controllers, the MDSS instances, the DP phys
and connect these together.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230111035906.2975494-2-quic_bjorande@quicinc.com