khugepaged: simplify the allocation of slab caches

Use the new KMEM_CACHE() macro instead of direct kmem_cache_create
to simplify the creation of SLAB caches.

Link: https://lkml.kernel.org/r/20240618014517.25954-1-lihongfu@kylinos.cnSigned-off-by: Hongfu Li <lihongfu@kylinos.cn>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged.c

@@ -385,10 +385,7 @@ int hugepage_madvise(struct vm_area_struct *vma,
 
 int __init khugepaged_init(void)
 {
-	mm_slot_cache = kmem_cache_create("khugepaged_mm_slot",
-					  sizeof(struct khugepaged_mm_slot),
-					  __alignof__(struct khugepaged_mm_slot),
-					  0, NULL);
+	mm_slot_cache = KMEM_CACHE(khugepaged_mm_slot, 0);
 	if (!mm_slot_cache)
 		return -ENOMEM;