write_tx_desc shouldn't pass a rt2x00dev and skb pointer,
instead it should use the same format as other TX frame
callback functions, which is passing the data_entry pointer
which contains all the information which is needed to work
on a TX frame.

Most callers of the kick_tx_queue and kill_tx_queue already
have the data_queue pointer, so rather then sending the QID
with the given function, when the driver requests a new
pointer to the data_queue, it is more efficient to just
send the data_queue pointer directly.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>