qed: iWARP - Fix default window size to be based on chip

The default window size is calculated for best performance based
on internal hw buffer sizes. The size differs between the
different chips and modes.

Fixes: 67b40dcc ("qed: Implement iWARP initialization, teardown and qp operations")
Signed-off-by: Ariel Elior <ariel.elior@marvell.com>
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>