drm/msm/dpu: fix writeback programming for YUV cases

drm/msm/dpu: fix writeback programming for YUV cases

[ Upstream commit 79caf2f2202b9eaad3a5a726e4b33807f67d0f1b ]

For YUV cases, setting the required format bits was missed
out in the register programming. Lets fix it now in preparation
of adding YUV formats support for writeback.

changes in v2:
    - dropped the fixes tag as its not a fix but adding
      new functionality

Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/571814/
Link: https://lore.kernel.org/r/20231212205254.12422-4-quic_abhinavk@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>