[PATCH v2] test/crypto: skip plain text compare for null cipher

[Akhil Goyal]

> >
> > Acked-by: Ciara Power <ciara.power at intel.com>
> 
> Wonder if this patch needs to CC stable, as it's fixing a commit from 2019?
> 
> Apart from this:
> Acked-by: Pablo de Lara <pablo.de.lara.guarch at intel.com>
Applied to dpdk-next-crypto

Cc: stable at dpdk.org