crypto: Kconfig - mark unused ciphers as obsolete

We have a few interesting pieces in our cipher museum, which are never
used internally, and were only ever provided as generic C implementations.

Unfortunately, we cannot simply remove this code, as we cannot be sure
that it is not being used via the AF_ALG socket API, however unlikely.

So let's mark the Anubis, Khazad, SEED and TEA algorithms as obsolete,
which means they can only be enabled in the build if the socket API is
enabled in the first place.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>