nfp: flower: remove unnecessary iteration over devices

For flower tunnel offloads FW has to be informed about MAC addresses
of tunnel devices.  We use a netdev notifier to keep track of these
addresses.

Remove unnecessary loop over netdevices after notifier is registered.
The intention of the loop was to catch devices which already existed
on the system before nfp driver got loaded, but netdev notifier will
replay NETDEV_REGISTER events.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>