mm/memcg: Convert mem_cgroup_charge() to take a folio

Convert all callers of mem_cgroup_charge() to call page_folio() on the
page they're currently passing in.  Many of them will be converted to
use folios themselves soon.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

mm/filemap.c

@@ -889,7 +889,7 @@ noinline int __add_to_page_cache_locked(struct page *page,
 	page->index = offset;
 
 	if (!huge) {
-		error = mem_cgroup_charge(page, NULL, gfp);
+		error = mem_cgroup_charge(page_folio(page), NULL, gfp);
 		if (error)
 			goto error;
 		charged = true;