!7742 netrom: Fix data-races around sysctl_net_busy_read

Merge Pull Request from: @ci-robot 
 
PR sync from: Hongbo Li <lihongbo22@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/LFCTMIMWO46Z6P6FDGUMIRH3VWB6KSA3/ 
 
https://gitee.com/src-openeuler/kernel/issues/I9Q94D 
 
Link:https://gitee.com/openeuler/kernel/pulls/7742

 

Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Reviewed-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Zhang Jianhua <chris.zjh@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>