drm/xe/vf: Don't allow GT reset to be queued during VF post migration recovery

drm/xe/vf: Don't allow GT reset to be queued during VF post migration recovery

With well-behaved software, a GT reset should never occur, nor should it
happen during VF post-migration recovery. If it does, trigger a warning
but suppress the GT reset, as VF post-migration recovery is expected to
bring the VF back to a working state.

v3:
 - Better commit message (Tomasz)
v5:
 - Use xe_gt_WARN_ON (Michal)

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Tomasz Lis <tomasz.lis@intel.com>
Link: https://lore.kernel.org/r/20251008214532.3442967-17-matthew.brost@intel.com