crypto: octeontx2 - add apis for custom engine groups

Octeon TX2 CPT has three type of engines to handle symmetric, asymmetric
and ipsec specific workload. For better utilization, these engines can
be grouped to custom groups at runtime.

This patch adds APIs to create and delete custom CPT engine groups.

Signed-off-by: Srujana Challa <schalla@marvell.com>
Signed-off-by: Shijith Thotton <sthotton@marvell.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>