mac80211: allow driver to disconnect after resume

mac80211: allow driver to disconnect after resume

In WoWLAN, devices may use crypto keys for TX/RX
and could also implement GTK rekeying. If the
driver isn't able to retrieve replay counters and
similar information from the device upon resume,
or if the device isn't responsive due to platform
issues, it isn't safe to keep the connection up
as GTK rekey messages from during the sleep time
could be replayed against it.

The only protection against that is disconnecting
from the AP. Modifying mac80211 to do that while
it is resuming would be very complex and invasive
in the case that the driver requires a reconfig,
so do it after it has resumed completely. In that
case, however, packets might be replayed since it
can then only happen after TX/RX are up again, so
mark keys for interfaces that need to disconnect
as "tainted" and drop all packets that are sent
or received with those keys.

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