cryptodev: add AEAD parameters in crypto operation

cryptodev: add AEAD parameters in crypto operation

AEAD operation parameters can be set in the new
aead structure, in the crypto operation.
This structure is within a union with the cipher
and authentication parameters, since operations can be:
- AEAD: using the aead structure

- Cipher only: using only the cipher structure

- Auth only: using only the authentication structure

- Cipher-then-auth/Auth-then-cipher: using both cipher
  and authentication structures

Therefore, all three cannot be used at the same time.

Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Acked-by: Declan Doherty <declan.doherty@intel.com>
Acked-by: Akhil Goyal <akhil.goyal@nxp.com>
Acked-by: Fiona Trahe <fiona.trahe@intel.com>