!886 net: sched: fix NULL pointer dereference in mq_attach

Merge Pull Request from: @ci-robot 
 
PR sync from:  Zhengchao Shao <shaozhengchao@huawei.com>
 https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/thread/XWHRWDMB4P3YRCQBLQMFWCV4DDLKNDHE/ 
 
 
Link:https://gitee.com/openeuler/kernel/pulls/886

 

Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>