net-sysfs: add a newline when printing 'tx_timeout' by sysfs

stable inclusion
from linux-4.19.136
commit ea19403632142656a0db5fc9501681ff9d5efe68

--------------------------------

[ Upstream commit 9bb5fbea ]

When I cat 'tx_timeout' by sysfs, it displays as follows. It's better to
add a newline for easy reading.

root@syzkaller:~# cat /sys/devices/virtual/net/lo/queues/tx-0/tx_timeout
0root@syzkaller:~#
Signed-off-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NLi Aichun <liaichun@huawei.com>
Reviewed-by: Nguodeqing <geffrey.guo@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/core/net-sysfs.c

@@ -1045,7 +1045,7 @@ static ssize_t tx_timeout_show(struct netdev_queue *queue, char *buf)
 	trans_timeout = queue->trans_timeout;
 	spin_unlock_irq(&queue->_xmit_lock);
 
-	return sprintf(buf, "%lu", trans_timeout);
+	return sprintf(buf, fmt_ulong, trans_timeout);
 }
 
 static unsigned int get_netdev_queue_index(struct netdev_queue *queue)