mac80211: initialise queue QoS parameters at hw start

When hardware is started it might be in a confused state with
respect to queue QoS parameters. This patch changes mac80211
to set sane defaults right after the hardware is brought up.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>