The TFCS bits show the current XON state.  Meaning that the
device is paused if these bits are 0.  This fixes the logic
to work as it was intended.
Signed-off-by: NJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>