crypto: ahash - fixed style error in ahash.c

Fixed style error identified by checkpatch.

WARNING: Missing a blank line after declarations
+               unsigned int unaligned = alignmask + 1 - (offset & alignmask);
+               if (nbytes > unaligned)

Signed-off-by: Joshua I. James <joshua@cybercrimetech.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>