drm/xe/vf: Start re-emission from first unsignaled job during VF migration

drm/xe/vf: Start re-emission from first unsignaled job during VF migration

The LRC software ring tail is reset to the first unsignaled pending
job's head.

Fix the re-emission logic to begin submitting from the first unsignaled
job detected, rather than scanning all pending jobs, which can cause
imbalance.

v2:
 - Include missing local changes
v3:
 - s/skip_replay/restore_replay (Tomasz)

Fixes: c25c1010df88 ("drm/xe/vf: Replay GuC submission state on pause / unpause")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Tomasz Lis <tomasz.lis@intel.com>
Link: https://patch.msgid.link/20251121152750.240557-1-matthew.brost@intel.com