drm/xe/oa/uapi: Add gt_id to struct drm_xe_oa_unit

drm/xe/oa/uapi: Add gt_id to struct drm_xe_oa_unit

gt_id was previously omitted from 'struct drm_xe_oa_unit' because it could
be determine from hwe's attached to the OA unit. However, we now have OA
units which don't have any hwe's attached to them. Hence add gt_id to
'struct drm_xe_oa_unit' in order to provide this needed information to
userspace.

Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Link: https://patch.msgid.link/20251202025115.373546-3-ashutosh.dixit@intel.com