When changing dev tx_queue_len via netlink or net-sysfs,
a NETDEV_CHANGE_TX_QUEUE_LEN event notification will be
called.

But dev_ioctl missed this event notification, which could
cause no userspace notification would be sent.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>