usb: typec: fix use after free in typec_register_port()

We can't use "port->sw" and/or "port->mux" after it has been freed.

Fixes: 23481121 ("usb: typec: class: Don't use port parent for getting mux handles")
Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Cc: stable <stable@vger.kernel.org>
Cc: linux-usb@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20191126140452.14048-1-wenyang@linux.alibaba.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/class.c

@@ -1612,14 +1612,16 @@ struct typec_port *typec_register_port(struct device *parent,
 
 	port->sw = typec_switch_get(&port->dev);
 	if (IS_ERR(port->sw)) {
+		ret = PTR_ERR(port->sw);
 		put_device(&port->dev);
-		return ERR_CAST(port->sw);
+		return ERR_PTR(ret);
 	}
 
 	port->mux = typec_mux_get(&port->dev, NULL);
 	if (IS_ERR(port->mux)) {
+		ret = PTR_ERR(port->mux);
 		put_device(&port->dev);
-		return ERR_CAST(port->mux);
+		return ERR_PTR(ret);
 	}
 
 	ret = device_add(&port->dev);