drm/xe: introduce xe_gt_reset and xe_gt_wait_for_reset

drm/xe: introduce xe_gt_reset and xe_gt_wait_for_reset

Add synchronous version gt reset as there are few places where it
is expected.
Also add a wait helper to wait until gt reset is done.

Signed-off-by: Maciej Patelczyk <maciej.patelczyk@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Fixes: f3bc5bb4d53d ("drm/xe: Allow userspace to configure CCS mode")
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241211111727.1481476-2-maciej.patelczyk@intel.com
Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>