mac80211: fix ignored HT/VHT override configs

HT and VHT override configurations were ignored during association and
applied only when first beacon recived, or not applied at all.

Fix the code to apply HT/VHT overrides during association. This is a bit
tricky since the channel was already configured during authentication
and we don't want to reconfigure it unless there's really a change.

Signed-off-by: Chaya Rachel Ivgi <chaya.rachel.ivgi@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>