mm: no need to cast vmalloc() return value in zone_wait_table_init()

vmalloc() returns a void pointer, so there's no need to cast its
return value in mm/page_alloc.c::zone_wait_table_init().
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -2444,7 +2444,7 @@ int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
 		 * To use this new node's memory, further consideration will be
 		 * necessary.
 		 */
-		zone->wait_table = (wait_queue_head_t *)vmalloc(alloc_size);
+		zone->wait_table = vmalloc(alloc_size);
 	}
 	if (!zone->wait_table)
 		return -ENOMEM;