mm/rmap: use folio_large_nr_pages() when we are sure it is a large folio

Non-large folio is handled at the beginning, so it is a large folio for
sure.

Use folio_large_nr_pages() here like elsewhere.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Wei Yang <[e-mail]>
Reviewed-by: Lorenzo Stoakes <[e-mail]>
Acked-by: David Hildenbrand <[e-mail]>
Cc: Rik van Riel <[e-mail]>
Cc: Liam R. Howlett <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Cc: Harry Yoo <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

mm/rmap.c

···
 			nr = folio_sub_return_large_mapcount(folio, nr_pages, vma);
 			if (!nr) {
 				/* Now completely unmapped. */
-				nr = folio_nr_pages(folio);
+				nr = folio_large_nr_pages(folio);
 			} else {
 				partially_mapped = nr < folio_large_nr_pages(folio) &&
 						   !folio_entire_mapcount(folio);