!4146 tcp: fix compilation issue when CONFIG_SYSCTL is disabled

Merge Pull Request from: @ci-robot 
 
PR sync from: Zhengchao Shao <shaozhengchao@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/NB6TAJPSOOCMAJIFS5OQ7VJCSDTSFVO6/ 
 
https://gitee.com/openeuler/kernel/issues/I8Y7PX 
 
Link:https://gitee.com/openeuler/kernel/pulls/4146

 

Reviewed-by: Yue Haibing <yuehaibing@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>