rtnetlink: bring NETDEV_CHANGE_TX_QUEUE_LEN event process back in rtnetlink_event

The same fix for changing mtu in the patch 'rtnetlink: bring
NETDEV_CHANGEMTU event process back in rtnetlink_event' is
needed for changing tx_queue_len.

Note that the redundant notifications issue for tx_queue_len
will be fixed in the later patch 'rtnetlink: do not send
notification for tx_queue_len in do_setlink'.

Fixes: 27b3b551 ("rtnetlink: Do not generate notifications for NETDEV_CHANGE_TX_QUEUE_LEN event")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/rtnetlink.c

@@ -4287,6 +4287,7 @@ static int rtnetlink_event(struct notifier_block *this, unsigned long event, voi
 	case NETDEV_NOTIFY_PEERS:
 	case NETDEV_RESEND_IGMP:
 	case NETDEV_CHANGEINFODATA:
+	case NETDEV_CHANGE_TX_QUEUE_LEN:
 		rtmsg_ifinfo_event(RTM_NEWLINK, dev, 0, rtnl_get_event(event),
 				   GFP_KERNEL);
 		break;