Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/video/fbdev/xen-fbfront.c b/drivers/video/fbdev/xen-fbfront.c
index 6a4bbc9..a3d6b6d 100644
--- a/drivers/video/fbdev/xen-fbfront.c
+++ b/drivers/video/fbdev/xen-fbfront.c
@@ -677,7 +677,7 @@
 	case XenbusStateClosed:
 		if (dev->state == XenbusStateClosed)
 			break;
-		/* Missed the backend's CLOSING state -- fallthrough */
+		/* fall through - Missed the backend's CLOSING state. */
 	case XenbusStateClosing:
 		xenbus_frontend_closed(dev);
 		break;