Revert "crypto: aesni - disable "by8" AVX CTR optimization"

This reverts commit 7da4b29d.

Now, that the issue is fixed, we can re-enable the code.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Chandramouli Narayanan <mouli@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>