drm/xe/sriov: Disable SR-IOV if primary GT is disabled via configfs

drm/xe/sriov: Disable SR-IOV if primary GT is disabled via configfs

SR-IOV operation relies on the primary GT's GuC to operate (in both PF
and VF mode).  Don't enable the .has_sriov flag if the primary-GT was
disabled by configfs.

v2:
 - Move handling to xe_info_init().  (Michal)

v3:
 - Just update the .has_sriov flag in xe_info_init_early().  (Michal)

v4:
 - Drop unnecessary comment.  (Michal)
 - Flip condition order for consistency with other checks.  (Michal)

Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://lore.kernel.org/r/20251013200944.2499947-48-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>