tipc: send explicit not supported error in nl compat

The legacy netlink API treated EPERM (permission denied) as
"operation not supported".

Reported-by: Tomi Ollila <tomi.ollila@iki.fi>
Signed-off-by: Richard Alpe <richard.alpe@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/netlink_compat.c

@@ -1121,7 +1121,7 @@ static int tipc_nl_compat_recv(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	err = tipc_nl_compat_handle(&msg);
-	if (err == -EOPNOTSUPP)
+	if ((err == -EOPNOTSUPP) || (err == -EPERM))
 		msg.rep = tipc_get_err_tlv(TIPC_CFG_NOT_SUPPORTED);
 	else if (err == -EINVAL)
 		msg.rep = tipc_get_err_tlv(TIPC_CFG_TLV_ERROR);