mlx4_en: eth statistics modification

In native mode display all available staticstics.
In SRIOV mode on VF display only SW counters statistics,
in SRIOV mode on hypervisor display SW counters and errors (got from FW)
statistics.

Signed-off-by: Eugenia Emantayev <eugenia@mellanox.co.il>
Reviewed-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>