ionic: refactor ionic_lif_addr to remove a layer

The filter counting in ionic_lif_addr() really isn't useful,
and potentially misleading, especially when we're checking in
ionic_lif_rx_mode() to see if we need to go into PROMISC mode.
We can safely refactor this and remove a calling layer.

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