mac80211: refuse TX queue configuration on non-QoS HW

Drivers that don't support QoS also don't support
setting up their ACs, catch that early. While at
it, remove the input check since cfg80211 does it
now.

Also fix up the restart code to not try to set up
the queues in this case.

Finally also change the tx_conf array to have
IEEE80211_NUM_ACS entries instead of # of queues
since that's what it really needs.

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