mlx4: remove order field from mlx4_en_frag_info

This is really a port attribute, no need to duplicate it per
RX queue and per frag.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>