mm, slab: Build fix for recent kmem_cache changes

Commit 3b0efdf ("mm, sl[aou]b: Extract common fields from struct
kmem_cache") renamed the kmem_cache structure's "next" field to "list"
but forgot to update one instance in leaks_show().

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
diff --git a/mm/slab.c b/mm/slab.c
index bb79652..d95ad4c 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -4533,7 +4533,7 @@
 
 static int leaks_show(struct seq_file *m, void *p)
 {
-	struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next);
+	struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list);
 	struct slab *slabp;
 	struct kmem_list3 *l3;
 	const char *name;