After 02e2065203, it can happen that both,
[VHT160-80PLUS80] and [VHT160] are added to the vht_capab option in
an AP's hostapd.conf, which would cause a failure to start the AP.
Fix the logic in order to prevent such misconfiguration.
Fixes: #22481
Signed-off-by: Shine <4c.fce2@proton.me>
Link: https://github.com/openwrt/openwrt/pull/22482
Signed-off-by: Robert Marko <robimarko@gmail.com>
c949d0e6c6