net/mlx5e: Provide correct packet/bytes statistics

Using the HW VPort counters for traffic (rx/tx packets/bytes)
statistics is wrong. This is because frames dropped due to steering or
out of buffer will be counted as received. To fix that, we move to use
the packet/bytes accounting done by the driver for what the netdev
reports out.

Fixes: f62b8bb8

 ('net/mlx5: Extend mlx5_core to support [...]')
Signed-off-by: Gal Pressman <galp@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>