ext4: Convert mext_page_mkuptodate() to take a folio

Use a folio throughout.  Does not support large folios due to
an array sized for MAX_BUF_PER_PAGE, but it does remove a few
calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20230324180129.1220691-28-willy@infradead.org


Signed-off-by: Theodore Ts'o <tytso@mit.edu>