ionic: fire watchdog again after fw_down

In some cases of fw_down it was called because there was a
fw_generation change, and the firmware is already back up.
In order to keep the down time to a minimum, don't wait for
the next watchdog polling cycle, fire another watchdog off
as soon as we can - an out-of-cycle check won't hurt, and
may well speed up the recovery.

Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>