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: c62987bbd8a1 ("bridge: push bridge setting ageing_time down to switchdev")
Signed-off-by: Haishuang Yan <[e-mail]>
Acked-by: Ido Schimmel <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/bridge/br_stp.c

···
 	int err;
 
 	err = switchdev_port_attr_set(br->dev, &attr);
-	if (err)
+	if (err && err != -EOPNOTSUPP)
 		return err;
 
 	br->ageing_time = t;