vdpa: document set_group_asid thread safety

Document that the function races with the check of DRIVER_OK.

Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20260119143306.1818855-6-eperezma@redhat.com>

Author: eugpermar

include/linux/vdpa.h

@@ -312,7 +312,9 @@ struct vdpa_map_file {
  *				@idx: virtqueue index
  *				Returns the affinity mask
  * @set_group_asid:		Set address space identifier for a
- *				virtqueue group (optional)
+ *				virtqueue group (optional).  Caller must
+ *				prevent this from being executed concurrently
+ *				with set_status.
  *				@vdev: vdpa device
  *				@group: virtqueue group
  *				@asid: address space id for this group