qed: Enlrage the drain timeout

In the scenario where slowpath configuration isn't passing due to
various pause configurations affecting the chip, the theoretical time
required in worst-case-scenario to empty hw fifos sufficiently to
guarantee that slowpath configuration would flow is currently
insufficient.

This increases such a drain request to the theoretical maximum.

Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>