drm/xe/uapi: Remove unused field of drm_xe_query_gt

We already have many bits reserved at the end already.
Let's kill the unused ones.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>