crypto: algapi - require cra_name and cra_driver_name

Now that all algorithms explicitly set cra_driver_name, make it required
for algorithm registration and remove the code that generated a default
cra_driver_name.

Also add an explicit check that cra_name is set too, since that's
obviously required too, yet it didn't seem to be checked anywhere.

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