cryptodev: add sym session header size function

cryptodev: add sym session header size function

This patch adds a new API in Cryptodev Framework. The API is used
to get the header size for the created symmetric Cryptodev session.

Signed-off-by: Fan Zhang <roy.fan.zhang@intel.com>
Acked-by: Fiona Trahe <fiona.trahe@intel.com>
Acked-by: Akhil Goyal <akhil.goyal@nxp.com>