crypto: chelsio - replace AES cipher calls with library calls

Replace a couple of occurrences where the "aes-generic" cipher is
instantiated explicitly and only used for encryption of a single block.
Use AES library calls instead.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>