xen/xenbus: Fixed indentation error in switch case

Fixed the indentation error in the switch case in
xenbus_dev_backend.c
Signed-off-by: Lisa Nguyen <lisa@xenapiadmin.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/xenbus/xenbus_dev_backend.c

@@ -80,10 +80,8 @@ static long xenbus_backend_ioctl(struct file *file, unsigned int cmd, unsigned l
 		if (xen_store_evtchn > 0)
 			return xen_store_evtchn;
 		return -ENODEV;
-
 	case IOCTL_XENBUS_BACKEND_SETUP:
 		return xenbus_alloc(data);
-
 	default:
 		return -ENOTTY;
 	}