Make Whirlpool use the _gcry_md_block_write helper
* cipher/whirlpool.c (whirlpool_context_t): Add 'bctx', remove 'buffer', 'count' and 'nblocks'. (whirlpool_init): Initialize 'bctx'. (whirlpool_transform): Adjust context argument type and burn stack depth. (whirlpool_add): Remove. (whirlpool_write): Use _gcry_md_block_write. (whirlpool_final, whirlpool_read): Adjust for 'bctx' usage.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>