ntfs3: Convert ntfs_read_folio to use a folio

Remove the struct page conversion, and use a folio throughout.  We still
convert back to a struct page for calling some internal functions,
but those will change soon.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>