net80211: fix IEEE80211_VFHT_BITS after 160 and 80P80 got swapped

Sponsored by: The FreeBSD Foundation
Fixes: 8f2e5b6ef3230
Reviewed by: adrian, thj
Differential Revision: https://reviews.freebsd.org/D49772

(cherry picked from commit 626a4931be7a095cff95e4272c7f36f9bedebeff)