cryptodev: support session private data setting

cryptodev: support session private data setting

The application may want to store private data along with the
rte_cryptodev that is transparent to the rte_cryptodev layer.
For e.g., If an eventdev based application is submitting a
rte_cryptodev_sym_session operation and wants to indicate event
information required to construct a new event that will be
enqueued to eventdev after completion of the rte_cryptodev_sym_session
operation. This patch provides a mechanism for the application
to associate this information with the rte_cryptodev_sym_session session.
The application can set the private data using
rte_cryptodev_sym_session_set_private_data() and retrieve it using
rte_cryptodev_sym_session_get_private_data().

Signed-off-by: Abhinandan Gujjar <abhinandan.gujjar@intel.com>
Signed-off-by: Nikhil Rao <nikhil.rao@intel.com>
Acked-by: Akhil Goyal <akhil.goyal@nxp.com>
Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>