mm: Export symbol __pud_trans_huge_lock

euleros inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8T1MB?from=project-issue


CVE: NA

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Export __pud_trans_huge_lock so that etmem_scan can exploit
this for page table walk.

__pud_trans_huge_lock returns page table lock pointer if a
given pud maps a transparent huge page, which will be useful
when encountering a pud entry during the page table walk
in etmem scan module.

Signed-off-by: Yuchen Tang <tangyuchen5@huawei.com>