crypto: hash - Remove legacy hash/digest implementaion

This patch removes the implementation of hash and digest now that
no algorithms use them anymore.  The interface though will remain
until the users are converted across.

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

diff --cc crypto/Makefile
Simple merge

diff --cc crypto/api.c
Simple merge

diff --cc crypto/internal.h
Simple merge