drm/xe/vf: Flush and stop CTs in VF post migration recovery

drm/xe/vf: Flush and stop CTs in VF post migration recovery

Flushing CTs (i.e., progressing all pending G2H messages) gives VF
post-migration recovery an accurate view of which H2G messages the GuC
has processed, enabling the GuC submission state machine to correctly
rebuild all state.

Also, stop all CT traffic, as the CT is not live during VF
post-migration recovery.

v3:
 - xe_guc_ct_flush_and_stop rename (Michal)
 - Drop extra GuC CT WQ wake up (Michal)

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://lore.kernel.org/r/20251008214532.3442967-21-matthew.brost@intel.com