dsa: do not support ndo_get_phys_port_name for non-legacy ports

Since each non-legacy slave has its own devlink port instance
correctly set, rely on devlink core to generate correct phys port name.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/slave.c

@@ -736,6 +736,13 @@ static int dsa_slave_get_phys_port_name(struct net_device *dev,
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
 
+	/* For non-legacy ports, devlink is used and it takes
+	 * care of the name generation. This ndo implementation
+	 * should be removed with legacy support.
+	 */
+	if (dp->ds->devlink)
+		return -EOPNOTSUPP;
+
 	if (snprintf(name, len, "p%d", dp->index) >= len)
 		return -EINVAL;