ath9k_htc: Remove HW queue translation

There is no need to determine the HW queue
for each packet that is transmitted. The endpoint
can be chosen directly based on the queue type
that mac80211 sends down.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>