bnx2x: fix crash while ethtool -t

commit 2df1a70a  "bnx2x: Support
for byte queue limits" has introduced an asymmetry in usage of
netdev_tx_completed_queue and netdev_tx_sent_queue. Missing
call to netdev_tx_sent_queue causes the crash during ethtool -t.

The patch adds the missing call.

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>