mac80211: add stations in order to the station list

During reconfig the station list is traversed in order and station are
added back to the driver. Make sure the stations are added to the driver
in the same order they were added to mac80211.

This has a real side effect - some drivers (iwlwifi) require TDLS
stations to be added only after the AP station for the same network.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>