drm/xe/vf: Introduce RESFIX start marker support

drm/xe/vf: Introduce RESFIX start marker support

In scenarios involving double migration, the VF KMD may encounter
situations where it is instructed to re-migrate before having the
opportunity to send RESFIX_DONE for the initial migration. This can occur
when the fix-up for the prior migration is still underway, but the VF KMD
is migrated again.

Consequently, this may lead to the possibility of sending two migration
notifications (i.e., pending fix-up for the first migration and a second
notification for the new migration). Upon receiving the first RES_FIX
notification, the GuC will resume VF submission on the GPU, potentially
resulting in undefined behavior, such as system hangs or crashes.

To avoid this, post migration, a marker is sent to the GUC prior to the
start of resource fixups to indicate start of resource fixups. The same
marker is sent along with RESFIX_DONE notification so that GUC can avoid
submitting jobs to HW in case of double migration.

Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Tomasz Lis <tomasz.lis@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patch.msgid.link/20251201095011.21453-8-satyanarayana.k.v.p@intel.com