drm/msm/dpu: modify encoder programming for CDM over DP

Adjust the encoder format programming in the case of video mode for DP
to accommodate CDM related changes.

Changes in v4:
	- Remove hw_cdm check in dpu_encoder_needs_periph_flush()
	- Remove hw_cdm check when getting the fmt_fourcc in
	  dpu_encoder_phys_vid_enable()

Changes in v2:
	- Move timing engine programming to a separate patch from this
	  one
	- Move update_pending_flush_periph() invocation completely to
	  this patch
	- Change the logic of dpu_encoder_get_drm_fmt() so that it only
	  calls drm_mode_is_420_only() instead of doing additional
	  unnecessary checks
	- Create new functions msm_dp_needs_periph_flush() and it's
	  supporting function dpu_encoder_needs_periph_flush() to check
	  if the mode is YUV420 and VSC SDP is enabled before doing a
	  peripheral flush

Signed-off-by: Paloma Arellano <quic_parellan@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/579641/
Link: https://lore.kernel.org/r/20240222194025.25329-17-quic_parellan@quicinc.com


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