mm/vmalloc.c: update the comment in __vmalloc_area_node()

Since c67dc624 ("mm/vmalloc: do not call kmemleak_free() on not yet
accounted memory"), the __vunmap() have been changed to __vfree(), so
update the confusing comment().
Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Roman Penyaev <rpenyaev@suse.de>
Link: https://lkml.kernel.org/r/20200927155409.GA3315@rlkSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -2447,7 +2447,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 			page = alloc_pages_node(node, alloc_mask|highmem_mask, 0);
 
 		if (unlikely(!page)) {
-			/* Successfully allocated i pages, free them in __vunmap() */
+			/* Successfully allocated i pages, free them in __vfree() */
 			area->nr_pages = i;
 			atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
 			goto fail;