arm64: dts: qcom: sc7180: Update dts for DP phy inside QMP phy

Drop the old node and add the new one in its place.

Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Jeykumar Sankaran <jsanka@codeaurora.org>
Cc: Chandan Uddaraju <chandanu@codeaurora.org>
Cc: Vara Reddy <varar@codeaurora.org>
Cc: Tanmay Shah <tanmay@codeaurora.org>
Cc: Rob Clark <robdclark@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
[dianders: Adjusted due to DP not itself not in upstream dts yet]
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210301133318.v2.1.Iad06142ceb8426ce5492737bf3d9162ed0dd2b55@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>