ieee80211_vht_get_vhtflags() is checking the htinfo IE for the 20/40MHz flag as part of deciding valid channel widths. However, in the hostapd path, the ASSOC_REQ/REASSOC_REQ path will parse the IEs, do some HT/VHT setup, then call ieee80211_ht_updatehtcap_final(). In a HT ASSOC/REASSOC request there won't be a HTINFO IE, however ieee80211_vht_get_vhtflags() still checks for it, leading to a panic. Instead, treat it as if we don't yet know if it's HT40 or not. I'm not sure if we should do that or have it just do _RETURN_CHAN_BITS(0). Differential Revision: https://reviews.freebsd.org/D50794