net/mlx4_en: Fix port counters statistics bitmask

Two counters (rx_chksum_complete and tx_chksum_offload) are not displayed
under SRIOV for the PF via ethtool because their bit mask is off, fix that.

Fixes: f8c6455b ('net/mlx4_en: Extend checksum offloading by CHECKSUM COMPLETE')
Fixes: 9fab426d ('mlx4: add a new xmit_more counter')

Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>