/*
* Unregister all algorithms associated with a crypto driver.
* If there are pending sessions using it, leave enough information
* around so that subsequent calls using those sessions will
* correctly detect the driver has been unregistered and reroute
* requests.
*
* XXX careful. Don't change this to call crypto_unregister() for each
* XXX registered algorithm unless you drop the mutex across the calls;
* XXX you can't take it recursively.
*/