drm/msm/dsi: use DRM DSC helpers for DSC setup

Use new DRM DSC helpers to setup DSI DSC configuration. The
initial_scale_value needs to be adjusted according to the standard, but
this is a separate change.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/539276/
Link: https://lore.kernel.org/r/20230329-rfc-msm-dsc-helper-v14-4-bafc7be95691@quicinc.com


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>