crypto: s5p - use correct block size of 1 for ctr(aes)

Align the s5p ctr(aes) implementation with other implementations
of the same mode, by setting the block size to 1.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Kamil Konieczny <k.konieczny@partner.samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>