cfg80211: fix more bugs in mlme handling

The "what-was-I-thinking-if-anything" patch. Clearly,
if cfg80211_send_disassoc() does wdev_lock() and then
calls __cfg80211_send_disassoc(), the latter shouldn't
lock again. And the sme_state test is ... no further
comments.

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