drm/xe: Mark preempt fence workqueue as reclaim

Preempt fences are in the path of reclaim, and we signal these fences in
the preempt workqueue. With that, we need to mark the preempt fence
workqueue with reclaim so that this workqueue can make forward progress
during reclaim.

Fixes: dd08ebf6 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241113171751.1677784-1-matthew.brost@intel.com