rapidio: rio: fix possible name leak in rio_register_mport()

In the Linux kernel, the following vulnerability has been resolved:

rapidio: rio: fix possible name leak in rio_register_mport()

If device_register() returns error, the name allocated by dev_set_name()
need be freed. It should use put_device() to give up the reference in the
error path, so that the name can be freed in kobject_cleanup(), and
list_del() is called to delete the port from rio_mports.