net: aquantia: increase max number of hw queues

Increase the upper limit of the hw queues up to 8.
This makes RSS better on multiheaded cpus.

This is a maximum AQC hardware supports in one traffic class.

The actual value is still limited by a number of available cpu cores.

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