mac80211: fix modprobe deadlock by not calling wep_init under rtnl_lock

- ieee80211_wep_init(), which is called with rtnl_lock held, blocks in
   request_module() [waiting for modprobe to load a crypto module].

 - modprobe blocks in a call to flush_workqueue(), when it closes a TTY
   [presumably when it exits].

 - The workqueue item linkwatch_event() blocks on rtnl_lock.

There's no reason for wep_init() to be called with rtnl_lock held, so
just move it outside the critical section.

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>