virtio: console: prevent use-after-free of port name in port unplug

Remove the debugfs path before freeing port->name, to prevent a possible
use-after-free.

Reported-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 4e380c1..e910bec 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1574,9 +1574,8 @@
 	device_destroy(pdrvdata.class, port->dev->devt);
 	cdev_del(port->cdev);
 
-	kfree(port->name);
-
 	debugfs_remove(port->debugfs_file);
+	kfree(port->name);
 
 	/*
 	 * Locks around here are not necessary - a port can't be