drm/msm/dpu: drop dpu_format_populate_layout from dpu_plane_sspp_atomic_update

The dpu_plane_prepare_fb() already calls dpu_format_populate_layout().
Store the generated layout in the plane state and drop this call from
dpu_plane_sspp_update().

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Tested-by: Abhinav Kumar <quic_abhinavk@quicinc.com> # sc7280
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/612240/
Link: https://lore.kernel.org/r/20240903-dpu-mode-config-width-v6-5-617e1ecc4b7a@linaro.org