ieee80211_add_htcap_vendor
uint8_t *ieee80211_add_htcap_vendor(uint8_t *, struct ieee80211_node *);
frm = ieee80211_add_htcap_vendor(frm, ni);
frm = ieee80211_add_htcap_vendor(frm, ni);
frm = ieee80211_add_htcap_vendor(frm, bss);
frm = ieee80211_add_htcap_vendor(frm, ni);