net: aquantia: get total counters from DMA block

aq_nic_update_ndev_stats pushes statistics to ndev->stats from
system interface. This is not always good because it counts packets/bytes
before any of rx filters (including mac filter).

Its better to report the packet/bytes statistics from DMA
counters which gives actual values of data transferred over pci.
System level stats is still available via ethtool.

Signed-off-by: Nikita Danilov <ndanilov@aquantia.com>
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: Dmitry Bogdanov <dmitry.bogdanov@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>