ext4: Convert ext4_page_nomap_can_writeout to ext4_folio_nomap_can_writeout

Its one caller already uses a folio.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20230324180129.1220691-22-willy@infradead.org


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