!4107 ntp: Avoid undefined behaviour in second_overflow()

Merge Pull Request from: @ci-robot 
 
PR sync from: Xiongfeng Wang <wangxiongfeng2@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/H6VMOCYQZPTR5NIVBBZROWPMAFXI62GJ/ 
Link: https://lore.kernel.org/lkml/CAK8P3a09XrQWSBJh5-t2WhUtMGvGQRE6coGyxjNDpX2k0bAyUg@mail.gmail.com/T/#t

https://gitee.com/openeuler/kernel/issues/I8XVTG 
 
Link:https://gitee.com/openeuler/kernel/pulls/4107

 

Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>