crypto: shash - remove crypto_shash_ctx_aligned()

crypto_shash_ctx_aligned() is no longer used, and it is useless now that
shash algorithms don't support nonzero alignmasks, so remove it.

Also remove crypto_tfm_ctx_aligned() which was only called by
crypto_shash_ctx_aligned().  It's unlikely to be useful again, since it
seems inappropriate to use cra_alignmask to represent alignment for the
tfm context when it already means alignment for inputs/outputs.

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