net: aquantia: improve LRO configuration

Default LRO HW configuration was very conservative.

Low Number of Descriptors per LRO Sequence, small session
timeout, inefficient settings in interrupt generation logic.

Change max number of LRO descriptors from 2 to 16 to
increase performance. Increase maximum coalescing interval
in HW to 250uS. Tune up HW LRO interrupt generation setting
to prevent hw issues with long LRO sessions.

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