!7851 netrom: Fix data-races around sysctl_netrom_network_ttl_initialiser

Merge Pull Request from: @ci-robot 
 
PR sync from: Zhao Wenhui <zhaowenhui8@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/KLP3LVDEMF32HWKNN7YK2MS5PVO56FJA/ 
 
https://gitee.com/src-openeuler/kernel/issues/I9Q91I 
 
Link:https://gitee.com/openeuler/kernel/pulls/7851

 

Reviewed-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>