drm/xe/gt: some error handling fixes

Make sure we pass along the correct errors.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>