crypto: hash - Removed vestigial ahash fields

The base field in ahash_tfm appears to have been cut-n-pasted from
ablkcipher.  It isn't needed here at all.  Similarly, the info field
in ahash_request also appears to have originated from its cipher
counter-part and is vestigial.

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