mm/shmem: turn shmem_should_replace_page into shmem_should_replace_folio

This is a straightforward conversion.

Link: https://lkml.kernel.org/r/20220504182857.4013401-20-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>