crypto: aesni - Merge INITIAL_BLOCKS_ENC/DEC

Use macro operations to merge implemetations of INITIAL_BLOCKS,
since they differ by only a small handful of lines.

Use macro counter \@ to simplify implementation.
Signed-off-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>