drm/xe/uapi: update used tracking kernel-doc

drm/xe/uapi: update used tracking kernel-doc

In commit 4d0b035fd6da ("drm/xe/uapi: loosen used tracking restriction")
we dropped the CAP_PERMON restriction but missed updating the
corresponding kernel-doc. Fix that.

v2 (Sanjay):
  - Don't drop the note around the extra cpu_visible_used expectations.

Reported-by: Ulisses Furquim <ulisses.furquim@intel.com>
Fixes: 4d0b035fd6da ("drm/xe/uapi: loosen used tracking restriction")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Sanjay Yadav <sanjay.kumar.yadav@intel.com>
Reviewed-by: Sanjay Yadav <sanjay.kumar.yadav@intel.com>
Link: https://patch.msgid.link/20260130125105.451229-2-matthew.auld@intel.com