ionic: no transition while stopping

Make sure we don't try to transition the fw_status_ready
while we're still in the FW_STOPPING state, else we can
get stuck in limbo waiting on a transition that already
happened.

While we're here we can remove a superfluous check on
the lif pointer.

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