Going through the Frame (Sub)types the "QOS Data" being called "QOS"
scheme leads to a naming conflict for QOS_CFPOLL and QOS_CFACKPOLL
(if added). Rename QOS* to QOS_DATA* to avoid the conflict and
to also better match the standards name.

No functional changes intended.

Sponsored by: The FreeBSD Foundation
MFC after: 5 days