arm64: dts: qcom: sc7180: assign DSI clock source parents

Assign DSI clock source parents to DSI PHY clocks.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Link: https://lore.kernel.org/r/20210709210729.953114-3-dmitry.baryshkov@linaro.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>