drivers: dio: add missing iounmap() in dio_init()

If kzalloc() fails, iounmap() need be called in error path.
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220511064506.3398512-1-yangyingliang@huawei.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/dio/dio.c

@@ -216,8 +216,11 @@ static int __init dio_init(void)
 
 		/* Found a board, allocate it an entry in the list */
 		dev = kzalloc(sizeof(struct dio_dev), GFP_KERNEL);
-		if (!dev)
+		if (!dev) {
+			if (scode >= DIOII_SCBASE)
+				iounmap(va);
 			return -ENOMEM;
+		}
 
 		dev->bus = &dio_bus;
 		dev->dev.parent = &dio_bus.dev;