mac80211: free all AP/VLAN keys at once

When the AP interface is stopped, free all AP and VLAN keys at
once to only require synchronize_net() once. Since that does
synchronize_net(), also move two such calls into the function
(using the new force_synchronize parameter) to avoid doing it
twice.

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

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

diff --cc net/mac80211/key.h
Simple merge