iwlwifi: mvm: update smart fifo / beacon filtering upon association

When we associate, we may have heard the beacon before the
association. In that case, BSS_CHANGED_BEACON_INFO will be
set along with BSS_CHANGED_ASSOC in changes in
bss_info_change.

In this case, we didn't update the smart fifo nor beacon
filtering leaving those two feature disabled.

Signed-off-by: Eran Harary <eran.harary@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>