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: 37b5e889 ("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>