eventdev: introduce event crypto adapter

eventdev: introduce event crypto adapter

This patch introduces event crypto adapter APIs. It
also provides information on working model/adapter
modes & their usage. Application is expected to use
this interface to transfer packets between the crypto
device & the event device.

Signed-off-by: Abhinandan Gujjar <abhinandan.gujjar@intel.com>
Signed-off-by: Nikhil Rao <nikhil.rao@intel.com>
Signed-off-by: Gage Eads <gage.eads@intel.com>
Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Acked-by: Akhil Goyal <akhil.goyal@nxp.com>