drm/i915/dp: Sync instead of try-sync commits when getting active pipes

drm/i915/dp: Sync instead of try-sync commits when getting active pipes

Sync instead of only try-sync non-blocking commits when getting the
active pipes through a given DP port. Atm intel_dp_get_active_pipes()
will only try to sync a given pipe and if that would block ignore the
pipe. This was supposed to avoid link retraining in case a pending
modeset would do that anyway, however that could incorrectly ignore
fastset pipes as well for instance (which don't retraing the link).
The TC port reset path needs to handle all pipes, even if a waiting for
a pending commit would block. To account for the above cases sync all
the pipes unconditionally.

This also prepares for a follow-up change enabling the DP tunnel BW
allocation mode which needs to ensure that all active pipes are synced
and returned from intel_dp_get_active_pipes().

v2:
- Add a separate function to try-sync the pipes. (Ville)
v3:
- Just sync the pipes unconditionally in intel_dp_get_active_pipes().
  (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com> (v2)
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240226185246.1276018-3-imre.deak@intel.com