LinuxKPI: 802.11: implement ieee80211_get_{he,eht}_iftype_cap{,_vif}

Implement the combination of all four functions, the *_vif versions
from mac80211.h as a wrapper to the non-*_vif ones in cfg80211.h.
Put the function pairs next to each other and in the right files
and harmonize argument naming, etc.

Both of them have shown up too often in the todo-tracing to bother
enough to implement them now for a time in the future when we will
support HE/EHT.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days