cfg80211/mac80211: allow management frame TX in AP mode

Enable management frame transmission and subscribing
to management frames through nl80211 in both cfg80211
and mac80211. Also update a few places that I forgot
to update for P2P-client mode previously, and fix a
small bug with non-action frames in this API.

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