mac80211: Fix memleak in nl80211 authentication on deinit

This file was forgotten from the quilt patch that added MLME
primitives, so the kfree on interface removal is missing. Fix this
potential memleak by freeing the temporary Authentication frame IEs
from SME when the interface is being removed.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>