net: dsa: make port_bridge_leave return void

netdev_upper_dev_unlink() which notifies NETDEV_CHANGEUPPER, returns
void, as well as del_nbp(). So there's no advantage to catch an eventual
error from the port_bridge_leave routine at the DSA level.

Make this routine void for the DSA layer and its existing drivers.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/dsa.h b/include/net/dsa.h
index 004e034..6463bb2 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -298,7 +298,7 @@
 	 */
 	int	(*port_bridge_join)(struct dsa_switch *ds, int port,
 				    struct net_device *bridge);
-	int	(*port_bridge_leave)(struct dsa_switch *ds, int port);
+	void	(*port_bridge_leave)(struct dsa_switch *ds, int port);
 	int	(*port_stp_update)(struct dsa_switch *ds, int port,
 				   u8 state);