Convert all the callers to call page_folio().  Most of them were already
using a head page, but a few of them I can't prove were, so this may
actually fix a bug.
Signed-off-by: NMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NMike Rapoport <rppt@linux.ibm.com>
Reviewed-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>