!8314 mcb: fix error handling in mcb_alloc_bus()

Merge Pull Request from: @ci-robot 
 
PR sync from: Hui Tang <tanghui20@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/ASFXPLZQYWMEMTZWVBOHFRLDGAHSG5NV/ 
 
https://gitee.com/src-openeuler/kernel/issues/I9R4M2 
 
Link:https://gitee.com/openeuler/kernel/pulls/8314

 

Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com>
Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>