drm/i915/dp: Reorder intel_dp_compute_config() a bit

drm/i915/dp: Reorder intel_dp_compute_config() a bit

Consolidate the double pfit call, and reorder things so that
intel_dp_output_format() and intel_dp_compute_link_config() are
back-to-back. They are intimately related, and will need to be
called twice to properly handle the "4:2:0 also" modes.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220322120015.28074-6-ville.syrjala@linux.intel.com
Reviewed-by: Uma Shankar <uma.shankar@intel.com>