Revert "fs:/dcache.c: fix negative dentry limit not complete problem"

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8WPQW


CVE: NA

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This reverts commit 9095bd86.

Look at limit_negative_dentry(), it maybe write dentry->d_flags, so this
function should be protect by dentry->d_lock. Howerver, there is no lock
to protect limit_negative_dentry() in fast_dput(), so revert this patch.

Signed-off-by: Long Li <leo.lilong@huawei.com>