crypto: talitos - fix hash on SEC1.

crypto: talitos - fix hash on SEC1.

On SEC1, hash provides wrong result when performing hashing in several
steps with input data SG list has more than one element. This was
detected with CONFIG_CRYPTO_MANAGER_EXTRA_TESTS:

[   44.185947] alg: hash: md5-talitos test failed (wrong result) on test vector 6, cfg="random: may_sleep use_finup src_divs=[<reimport>25.88%@+8063, <flush>24.19%@+9588, 28.63%@+16333, <reimport>4.60%@+6756, 16.70%@+16281] dst_divs=[71.61%@alignmask+16361, 14.36%@+7756, 14.3%@+"
[   44.325122] alg: hash: sha1-talitos test failed (wrong result) on test vector 3, cfg="random: inplace use_final src_divs=[<flush,nosimd>16.56%@+16378, <reimport>52.0%@+16329, 21.42%@alignmask+16380, 10.2%@alignmask+16380] iv_offset=39"
[   44.493500] alg: hash: sha224-talitos test failed (wrong result) on test vector 4, cfg="random: use_final nosimd src_divs=[<reimport>52.27%@+7401, <reimport>17.34%@+16285, <flush>17.71%@+26, 12.68%@+10644] iv_offset=43"
[   44.673262] alg: hash: sha256-talitos test failed (wrong result) on test vector 4, cfg="random: may_sleep use_finup src_divs=[<reimport>60.6%@+12790, 17.86%@+1329, <reimport>12.64%@alignmask+16300, 8.29%@+15, 0.40%@+13506, <reimport>0.51%@+16322, <reimport>0.24%@+16339] dst_divs"

This is due to two issues:
- We have an overlap between the buffer used for copying the input
data (SEC1 doesn't do scatter/gather) and the chained descriptor.
- Data copy is wrong when the previous hash left less than one
blocksize of data to hash, implying a complement of the previous
block with a few bytes from the new request.

Fix it by:
- Moving the second descriptor after the buffer, as moving the buffer
after the descriptor would make it more complex for other cipher
operations (AEAD, ABLKCIPHER)
- Skip the bytes taken from the new request to complete the previous
one by moving the SG list forward.

Fixes: 37b5e8897eb5 ("crypto: talitos - chain in buffered data for ahash on SEC1")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>