A trivial cleanup to move clearing of RestoreReserve into adding anon rmap
of private hugetlb mappings.  It matches with the shared mappings where we
only clear the bit when adding into page cache, rather than spreading it
around the code paths.

Link: https://lkml.kernel.org/r/20221020193832.776173-1-peterx@redhat.comSigned-off-by: NPeter Xu <peterx@redhat.com>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>