ionic: replay filters after fw upgrade

The NIC's filters are lost in the midst of the fw-upgrade
so we need to replay them into the FW.  We also remove the
unused ionic_rx_filter_del() function.

Fixes: c672412f ("ionic: remove lifs on fw reset")
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>