drm/msm/dsi: stop setting clock parents manually

There is no reason to set clock parents manually, use device tree to
assign DSI/display clock parents to DSI PHY clocks. Dropping this manual
setup allows us to drop repeating code and to move registration of hw
clock providers to generic place.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Link: https://lore.kernel.org/r/20211006204828.1218225-2-dmitry.baryshkov@linaro.org


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>