drm/xe/pf: Force new VFs prorities only once

drm/xe/pf: Force new VFs prorities only once

We should force change of VFs scheduling priorities only after
initial change of the SCHED_IF_IDLE policy. Doing that also during
any later policy reprovisioning will overwrite changes done on the
individual per-VF scheduling priorities (currently only for PF).

While around also move priority change code to the _config component
to maintain a proper isolation. Also document our expectation about
the GuC version where the new meaning of the policy KLV is present.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://patch.msgid.link/20260402191726.4932-4-michal.wajdeczko@intel.com