mac80211: fix suspend vs. association race

If the association is in progress while we suspend, the
stack will be in a messed up state. Clean it before we
suspend.

This patch completes Johannes's patch:

1a1cb744
Author: Johannes Berg <johannes.berg@intel.com>

    mac80211: fix suspend vs. authentication race

Cc: <stable@vger.kernel.org>
Fixes: 12e7f517 ("mac80211: cleanup generic suspend/resume procedures")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>