crypto: aes - rename local routines to prevent future clashes

Rename some local AES encrypt/decrypt routines so they don't clash with
the names we are about to introduce for the routines exposed by the
generic AES library.

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