net: aquantia: Introduce firmware ops callbacks

New AQC cards will have an updated firmware with new binary interface.
This patch extracts firmware specific operations into a separate table
and prepares for the introduction of new fw 2.x and 3.x

Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>