The overrun ignore bit isn't supported by the device's firmware and was
recently removed from the programmer's reference manual (PRM).

Remove it from the driver as well.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>