RTW_NTXDESCBCN
&sc->sc_descs->hd_bcn[0], RTW_NTXDESCBCN,
RTW_NTXDESCBCN - 1};
RTW_NTXDESCHI + RTW_NTXDESCBCN)
struct rtw_txdesc hd_bcn[RTW_NTXDESCBCN];