ll any device send nullfunc
frames and need to know whether they should be
QoS frames or not. In other modes, there are
(currently) no frames the device is supposed to
send.

When you now consider virtual interfaces, it
becomes apparent that the current mechanism is
inadequate since it enables/disables QoS on a
global scale, where for nullfunc frames it has
to be on a per-interface scale.

Due to the above considerations, we can change
the way mac80211 advertises the QoS state to
drivers to only ever advertise it as "off" in
station mode, and make it a per-BSS setting.

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