userfaultfd: convert mfill_atomic() to use a folio

userfaultfd: convert mfill_atomic() to use a folio

Convert mfill_atomic_pte_copy(), shmem_mfill_atomic_pte() and
mfill_atomic_pte() to take in a folio pointer.  Convert mfill_atomic() to
use a folio.  Convert page_kaddr to kaddr in mfill_atomic().

Link: https://lkml.kernel.org/r/20230331093937.945725-7-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>