mac80211: fail authentication when AP denied authentication

ieee80211_rx_mgmt_auth() doesn't handle denied authentication
properly - it authenticates the station and waits for association
(for 5 seconds) instead of failing the authentication.

Fix it by destroying auth_data and bailing out instead.

Signed-off-by: Eliad Peller <eliad@wizery.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Cc: stable@vger.kernel.org #3.4
Signed-off-by: John W. Linville <linville@tuxdriver.com>