usb: typec: class: Invalidate USB device pointers on partner unregistration

To avoid using invalid USB device pointers after a Type-C partner
disconnects, this patch clears the pointers upon partner unregistration.
This ensures a clean state for future connections.

Cc: stable@vger.kernel.org
Fixes: 59de2a5 ("usb: typec: Link enumerated USB devices with Type-C partner")
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
Link: https://lore.kernel.org/r/20250321143728.4092417-3-akuchynski@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Andrei Kuchynski

drivers/usb/typec/class.c

@@ -1086,10 +1086,14 @@ void typec_unregister_partner(struct typec_partner *partner)
 	port = to_typec_port(partner->dev.parent);
 
 	mutex_lock(&port->partner_link_lock);
-	if (port->usb2_dev)
+	if (port->usb2_dev) {
 		typec_partner_unlink_device(partner, port->usb2_dev);
-	if (port->usb3_dev)
+		port->usb2_dev = NULL;
+	}
+	if (port->usb3_dev) {
 		typec_partner_unlink_device(partner, port->usb3_dev);
+		port->usb3_dev = NULL;
+	}
 
 	device_unregister(&partner->dev);
 	mutex_unlock(&port->partner_link_lock);