Revert "mtd/ubi/block: Fix uaf problem in ubiblock_cleanup"

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8ZCT1


CVE: NA

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This reverts commit f13656bb.

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>