drm/msm/disp/dpu1: remove superfluous init

drm/msm/disp/dpu1: remove superfluous init

Commit c751db9dab4d ("drm/msm/disp/dpu1: Add support for DSC in
encoder") added dsc_common_mode variable which was set to zero but then
again programmed, so drop the superfluous init.

Fixes: c751db9dab4d ("drm/msm/disp/dpu1: Add support for DSC in encoder")
Reported-by: kernel test robot <yujie.liu@intel.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Patchwork: https://patchwork.freedesktop.org/patch/487208/
Link: https://lore.kernel.org/r/20220525073912.2706505-1-vkoul@kernel.org
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>