drm/xe/pf: Prepare to stop SR-IOV support prior GT reset

drm/xe/pf: Prepare to stop SR-IOV support prior GT reset

As part of the resume or GT reset, the PF driver schedules work
which is then used to complete restarting of the SR-IOV support,
including resending to the GuC configurations of provisioned VFs.

However, in case of short delay between those two actions, which
could be seen by triggering a GT reset on the suspened device:

 $ echo 1 > /sys/kernel/debug/dri/0000:00:02.0/gt0/force_reset

this PF worker might be still busy, which lead to errors due to
just stopped or disabled GuC CTB communication:

 [ ] xe 0000:00:02.0: [drm:xe_gt_resume [xe]] GT0: resumed
 [ ] xe 0000:00:02.0: [drm] GT0: trying reset from force_reset_show [xe]
 [ ] xe 0000:00:02.0: [drm] GT0: reset queued
 [ ] xe 0000:00:02.0: [drm] GT0: reset started
 [ ] xe 0000:00:02.0: [drm:guc_ct_change_state [xe]] GT0: GuC CT communication channel stopped
 [ ] xe 0000:00:02.0: [drm:guc_ct_send_recv [xe]] GT0: H2G request 0x5503 canceled!
 [ ] xe 0000:00:02.0: [drm] GT0: PF: Failed to push VF1 12 config KLVs (-ECANCELED)
 [ ] xe 0000:00:02.0: [drm] GT0: PF: Failed to push VF1 configuration (-ECANCELED)
 [ ] xe 0000:00:02.0: [drm:guc_ct_change_state [xe]] GT0: GuC CT communication channel disabled
 [ ] xe 0000:00:02.0: [drm] GT0: PF: Failed to push VF2 12 config KLVs (-ENODEV)
 [ ] xe 0000:00:02.0: [drm] GT0: PF: Failed to push VF2 configuration (-ENODEV)
 [ ] xe 0000:00:02.0: [drm] GT0: PF: Failed to push 2 of 2 VFs configurations
 [ ] xe 0000:00:02.0: [drm:pf_worker_restart_func [xe]] GT0: PF: restart completed

While this VFs reprovisioning will be successful during next spin
of the worker, to avoid those errors, make sure to cancel restart
worker if we are about to trigger next reset.

Fixes: 411220808cee ("drm/xe/pf: Restart VFs provisioning after GT reset")
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://lore.kernel.org/r/20250711193316.1920-2-michal.wajdeczko@intel.com