mac80211: vht: add support VHT EXT NSS BW in parsing VHT

This fixes was missed in parsing the vht capabilities max bw
support.

Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Fixes: e80d6425 ("mac80211: copy VHT EXT NSS BW Support/Capable data to station")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/20190830114057.22197-1-luca@coelho.fi


Signed-off-by: Johannes Berg <johannes.berg@intel.com>