mac80211: notify upper layers after lower

When drivers receive change notification they may do work that
will enable the changes to take effect. For example, if new association
the device needs to be programmed with this information.
Give the driver chance to make the changes before notifying the
upper layer - thus preventing race condition where upper layer
attempts to utilize state that may not be configured yet.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>