net: ethernet: ti: am65-cpsw: set correct devlink flavour for unused ports

am65_cpsw_nuss_register_ndevs() skips calling devlink_port_type_eth_set()
for ports without assigned netdev, triggering the following warning when
DEVLINK_PORT_TYPE_WARN_TIMEOUT elapses after 3600s:

    Type was not set for devlink port.
    WARNING: CPU: 0 PID: 129 at net/core/devlink.c:8095 devlink_port_type_warn+0x18/0x30

Fixes: 0680e20a

 ("net: ethernet: ti: am65-cpsw: Fix devlink port register sequence")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>