net80211: update (parts of) frame types and subtypes and annotate

Update to the full list of frame type and subtype values based on
802.11-2020 with 11ax and 11ay extensions. This includes the 4th type
"Extension" (IEEE80211_FC0_TYPE_EXT).
While here annotate them with descriptions which should help matching
names (as at times things get confusing with LinuxKPI).
Also remove some 802.11-1997 values Reserved nowadays.

No functional changes.

Sponsored by: The FreeBSD Foundation
MFC after: 5 days
Reviewed by: adrian
Differential Revision: https://reviews.freebsd.org/D36410