Fix warning on WIN32

Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

block/raw-win32.c

@@ -388,7 +388,6 @@ static void bdrv_raw_init(void)
 {
     bdrv_register(&bdrv_raw);
     bdrv_register(&bdrv_host_device);
-    return 0;
 }
 
 block_init(bdrv_raw_init);