cryptodev: set AES-GMAC as auth-only algo

cryptodev: set AES-GMAC as auth-only algo

AES-GMAC is an authentication algorithm, based on AES-GCM
without encryption. To simplify its usage, now it can be used
setting the authentication parameters, without requiring
to concatenate a ciphering transform.

Therefore, it is not required to set AAD, but authentication
data length and offset, giving the user the option
to have Scatter-Gather List in the input buffer,
as long as the driver supports it.

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>