mac80211: move managed mode station state modification

Move the station state modification right before insert,
this just makes the current code more readable (you can
tell that it's before insertion looking at a single
screenful of code) right now, but some upcoming changes
will require this.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>