drm/i915/display: Add new member to configure PCON color conversion

The decision to use DFP output format conversion capabilities should be
during compute_config phase.

This patch adds new member to crtc_state to represent the final
output_format to the sink. In case of a DFP this can be different than
the output_format, as per the format conversion done via the PCON.

This will help to store only the format conversion capabilities of the
DP device in intel_dp->dfp, and use crtc_state to compute and store the
configuration for color/format conversion for a given mode.

v2: modified the new member to crtc_state to represent the final
output_format that eaches the sink, after possible conversion by
PCON kind of devices. (Ville)

v3: Addressed comments from Ville:
-Added comments to clarify difference between sink_format and
output_format.
-Corrected the order of setting sink_format and output_format.
-Added readout for sink_format in get_pipe_config hooks.

v4: Set sink_format for intel_sdvo too. (Ville)

v5: Rebased.

v6: Fixed condition to go for YCbCr420 format for dp and hdmi. (Ville)

v7: Fix the condition to set sink_format for HDMI.
Set hdmi output_format simply as sink_format. (Ville)

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (v3)
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230427125605.487769-2-ankit.k.nautiyal@intel.com