bridge: Allow set bridge ageing time when switchdev disabled

When NET_SWITCHDEV=n, switchdev_port_attr_set will return -EOPNOTSUPP,
we should ignore this error code and continue to set the ageing time.

Fixes: c62987bb ("bridge: push bridge setting ageing_time down to switchdev")
Signed-off-by: NHaishuang Yan <yanhaishuang@cmss.chinamobile.com>
Acked-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_stp.c

@@ -582,7 +582,7 @@ int br_set_ageing_time(struct net_bridge *br, u32 ageing_time)
 	int err;
 
 	err = switchdev_port_attr_set(br->dev, &attr);
-	if (err)
+	if (err && err != -EOPNOTSUPP)
 		return err;
 
 	br->ageing_time = t;