drm/msm/dpu: Move setting of dpu_enc::wide_bus_en to atomic enable()

drm/msm/dpu: Move setting of dpu_enc::wide_bus_en to atomic enable()

Move the setting of dpu_enc::wide_bus_en to
dpu_encoder_virt_atomic_enable() so that it mirrors how dpu_enc::dsc
is being set.

Since wide bus for DSI is related to DSC, having it mirror how DSC
is set in DPU will also make it easier to accommodate for the possibility
of DSC for DSI being set during runtime in the future.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/553759/
Link: https://lore.kernel.org/r/20230822-add-widebus-support-v4-1-9dc86083d6ea@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>