mwl8k: differentiate between WMM queues and AMPDU queues

We now have two different kinds of queues.  And the number of
AMPDU queues may vary.  So we must be clear about which queues we
are dealing with.  Note that when we report the number of queues
to mac80211, we only report the WMM queues.

Based on work by Yogesh Powar <yogeshp@marvell.com>.

Signed-off-by: Brian Cavagnolo <brian@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>