net: hns3: replace snprintf with scnprintf in hns3_dbg_cmd_read

mainline inclusion
from mainline-v5.6-rc1
commit 49e211c0
category: bugfix
bugzilla: NA
CVE: NA

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

The return value of snprintf may be greater than the size of
HNS3_DBG_READ_LEN, use scnprintf instead in hns3_dbg_cmd_read.
Signed-off-by: NChen Zhou <chenzhou10@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NYonglong Liu <liuyonglong@huawei.com>
Reviewed-by: NYongxin Li <liyongxin1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c

@@ -304,8 +304,8 @@ static ssize_t hns3_dbg_cmd_read(struct file *filp, char __user *buffer,
 	if (!buf)
 		return -ENOMEM;
 
-	len = snprintf(buf, HNS3_DBG_READ_LEN, "%s\n",
-		       "Please echo help to cmd to get help information");
+	len = scnprintf(buf, HNS3_DBG_READ_LEN, "%s\n",
+			"Please echo help to cmd to get help information");
 	uncopy_bytes = copy_to_user(buffer, buf, len);
 
 	kfree(buf);