The 82598 has an erratum that receipt of pause frames at 1G
could lead to a Tx Hang.  To avoid this this patch disables
Rx FC while at 1G speed for all 82598 parts.
Signed-off-by: NDon Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>