drm/xe/bo: Redirect faults to dummy page for wedged device

As per uapi documentation[1], the prerequisite for wedged device is to
redirected page faults to a dummy page. Follow it.

[1] Documentation/gpu/drm-uapi.rst

v2: Add uapi reference and fixes tag (Matthew Brost)

Fixes: 7bc0075 ("drm/xe: Use device wedged event")
Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260212055622.2054991-1-raag.jadav@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
(cherry picked from commit c020fff)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Author: raagjadav

drivers/gpu/drm/xe/xe_bo.c

@@ -1941,7 +1941,7 @@ static vm_fault_t xe_bo_cpu_fault(struct vm_fault *vmf)
 	int err = 0;
 	int idx;
 
-	if (!drm_dev_enter(&xe->drm, &idx))
+	if (xe_device_wedged(xe) || !drm_dev_enter(&xe->drm, &idx))
 		return ttm_bo_vm_dummy_page(vmf, vmf->vma->vm_page_prot);
 
 	ret = xe_bo_cpu_fault_fastpath(vmf, xe, bo, needs_rpm);