o add IEEE80211_C_STA capability to indicate sta mode is supported
(was previously assumed) and mark drivers as capable
o add ieee80211_opcap array to map an opmode to the equivalent capability bit
o move IEEE80211_C_OPMODE definition to where capabilities are defined so it's
clear it should be kept in sync (on future additions)
o check device capabilities in clone create before trying to create a vap;
this makes driver checks unneeded
o make error codes return on failed clone request unique
o temporarily add console printfs on clone request failures to aid in
debugging; these will move under DIAGNOSTIC or similar before release
c43feede8b