crypto: algapi - remove unused notifications

There is a message posted to the crypto notifier chain when an algorithm
is unregistered, and when a template is registered or unregistered.  But
nothing is listening for those messages; currently there are only
listeners for the algorithm request and registration messages.

Get rid of these unused notifications for now.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>