drm/xe: Take PM ref in delayed snapshot capture worker

The delayed snapshot capture worker can access the GPU or VRAM both of
which require a PM reference. Take a reference in this worker.

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: 4f04d07c ("drm/xe: Faster devcoredump")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241126174615.2665852-5-matthew.brost@intel.com


(cherry picked from commit 1c6878af)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>