rtnetlink: ignore NETDEV_RELEASE and NETDEV_JOIN event

These two events are not expected to be caught by userspace.

Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/rtnetlink.c

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d2ba259..d1644e3 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1956,6 +1956,8 @@
 	case NETDEV_GOING_DOWN:
 	case NETDEV_UNREGISTER:
 	case NETDEV_UNREGISTER_BATCH:
+	case NETDEV_RELEASE:
+	case NETDEV_JOIN:
 		break;
 	default:
 		rtmsg_ifinfo(RTM_NEWLINK, dev, 0);