drm/xe: s/xe_tile_migrate_engine/xe_tile_migrate_exec_queue

Engine is old nomenclature, replace with exec queue.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240704041652.272920-2-matthew.brost@intel.com