crypto: hash - Fix handling of unaligned buffers

The correct way to calculate the start of the aligned part of an
unaligned buffer is:

  offset = ALIGN(offset, alignmask + 1);

However, crypto_hash_walk_done() has:

  offset += alignmask - 1;
  offset = ALIGN(offset, alignmask + 1);

which actually skips a whole block unless offset % (alignmask + 1) == 1.

This patch fixes the problem.
Signed-off-by: Szilveszter Ördög <slipszi@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/ahash.c

@@ -78,7 +78,6 @@ int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
 	walk->data -= walk->offset;
 
 	if (nbytes && walk->offset & alignmask && !err) {
-		walk->offset += alignmask - 1;
 		walk->offset = ALIGN(walk->offset, alignmask + 1);
 		walk->data += walk->offset;