Change the logic how acceleration engines are indexed to make it
easier to read. Aslo some return code values updates to better reflect
what failed.
Signed-off-by: NPingchao Yang <pingchao.yang@intel.com>
Signed-off-by: NTadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>