Revert "mac80211: keep sending peer candidate events while in listen state"

This reverts commit 2ae70efc.

The new peer events that are generated by the change are causing problems
with wpa_supplicant in userspace: wpa_s tries to restart SAE authentication
with the peer when receiving the event, even though authentication may be in
progress already, and it gets very confused.

Revert back to the original operating mode, which is to only get events when
there is no corresponding station entry.

Cc: Nishikawa, Kenzoh <Kenzoh.Nishikawa@jp.sony.com>
Cc: Masashi Honma <masashi.honma@gmail.com>
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>