Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index 581c4e1..833b2d2 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -544,7 +544,7 @@
 		xenbus_switch_state(xdev, XenbusStateClosed);
 		if (xenbus_dev_is_online(xdev))
 			break;
-		/* fall through if not online */
+		/* fall through - if not online */
 	case XenbusStateUnknown:
 		dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
 		device_unregister(&xdev->dev);
@@ -697,7 +697,7 @@
 	/* We need to force a call to our callback here in case
 	 * xend already configured us!
 	 */
-	xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);
+	xen_pcibk_be_watch(&pdev->be_watch, NULL, NULL);
 
 out:
 	return err;