cxgb3: No need to wake queue in xmit handler

The xmit handler doesn't need to wake the queue after stopping
it temporarily (some other drivers are doing the same).

Patch on net-next-2.6, multiple netperf sessions tested.

Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Acked-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>