!4707 mtd: Fix gluebi NULL pointer dereference caused by ftl notifier

Merge Pull Request from: @ci-robot 
 
PR sync from: ZhaoLong Wang <wangzhaolong1@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/ZKBKQS653TICO4XO64XLYBTVE3D4UG2K/ 
 
https://gitee.com/src-openeuler/kernel/issues/I932W5 
 
Link:https://gitee.com/openeuler/kernel/pulls/4707

 

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