drm/xe/guc: Check GuC running state before deregistering exec queue

drm/xe/guc: Check GuC running state before deregistering exec queue

In normal operation, a registered exec queue is disabled and
deregistered through the GuC, and freed only after the GuC confirms
completion. However, if the driver is forced to unbind while the exec
queue is still running, the user may call exec_destroy() after the GuC
has already been stopped and CT communication disabled.

In this case, the driver cannot receive a response from the GuC,
preventing proper cleanup of exec queue resources. Fix this by directly
releasing the resources when GuC is not running.

Here is the failure dmesg log:
"
[  468.089581] ---[ end trace 0000000000000000 ]---
[  468.089608] pci 0000:03:00.0: [drm] *ERROR* GT0: GUC ID manager unclean (1/65535)
[  468.090558] pci 0000:03:00.0: [drm] GT0:     total 65535
[  468.090562] pci 0000:03:00.0: [drm] GT0:     used 1
[  468.090564] pci 0000:03:00.0: [drm] GT0:     range 1..1 (1)
[  468.092716] ------------[ cut here ]------------
[  468.092719] WARNING: CPU: 14 PID: 4775 at drivers/gpu/drm/xe/xe_ttm_vram_mgr.c:298 ttm_vram_mgr_fini+0xf8/0x130 [xe]
"

v2: use xe_uc_fw_is_running() instead of xe_guc_ct_enabled().
    As CT may go down and come back during VF migration.

Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: stable@vger.kernel.org
Cc: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20251010172529.2967639-2-shuicheng.lin@intel.com