After 8.0-RELEASE, iwi(4) doesn't send any data frames in infrastructure
mode.
Bacause of the condition `while (frm < efrm)', IEEE80211_VERIFY_LENGTH()
was checking item length beyond the ieee80211_frame region, and returned
from iwi_checkforqos() without setting flags, capinfo and associd.
In infrastructure mode associd is required, so this problem causes
discarding mbuf in ieee80211_start().
PR: kern/165819
Tested/Reviewed/Supported by: bschmidt and adrian
MFC after: 1 week
7199b6f7ee