crypto: arm64/aes-neon - limit exposed routines if faster driver is enabled

The pure NEON AES implementation predates the bit-slicing one, and is
generally slower, unless the algorithm in question can only execute
sequentially.

So advertising the skciphers that the bit-slicing driver implements as
well serves no real purpose, and we can just disable them. Note that the
bit-slicing driver also has a link time dependency on the pure NEON
driver, for CBC encryption and for XTS tweak calculation, so we still
need both drivers on systems that do not implement the Crypto Extensions.

At the same time, expose those modaliases for the AES instruction based
driver. This is necessary since otherwise, we may end up loading the
wrong driver when any of the skciphers are instantiated before the CPU
capability based module loading has completed.

Finally, add the missing modalias for cts(cbc(aes)) so requests for
this algorithm will autoload the correct module.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>