rt2x00: rt2x00dev: use rt2x00dev->tx->limit

The TX data queue is initialized already when
the rt2x00lib_probe_hw() function is called.

Fetch the number of the queue entries from that
instead of using the entry_num field of the data
queue descriptor.

The two values are the same, and the use of the
rt2x00dev->tx->limit value allows us to get rid
of a superfluous pointer dereference.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2x00dev.c

@@ -1077,7 +1077,7 @@ static int rt2x00lib_probe_hw(struct rt2x00_dev *rt2x00dev)
 		 */
 		int kfifo_size =
 			roundup_pow_of_two(rt2x00dev->ops->tx_queues *
-					   rt2x00dev->ops->tx->entry_num *
+					   rt2x00dev->tx->limit *
 					   sizeof(u32));
 
 		status = kfifo_alloc(&rt2x00dev->txstatus_fifo, kfifo_size,