wl1251: implement WMM

Now that necessary commands for WMM are implemented, implement queue handling
for WMM. But WMM is not enabled yet, only one queue is used.

Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Reviewed-by: Janne Ylalehto <janne.ylalehto@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>