Add xcbc(aes) offloading support.

Due to xcbc algorithm design and HW implementation in CAAM,
driver must still have some bytes to send to the crypto engine when
ahash_final() is called - such that HW correctly uses either K2 or K3
for the last block.
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>