mac80211: flush keys when stopping AP

Since hostapd will remove keys this isn't usually
an issue, but we shouldn't leak keys to the next
BSS started on the same interface. For VLANs this
also fixes a bug, keys that aren't removed would
otherwise be leaked.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --cc net/mac80211/cfg.c
Simple merge

diff --cc net/mac80211/iface.c
Simple merge