[PATCH v3] test/crypto: fix enqueue dequeue callback case

[Akhil Goyal]

> Tested cryptodev_qat_autotest and cryptodev_null_autotest this patch along
> with https://patches.dpdk.org/project/dpdk/patch/20240416081222.3002268-1-ganapati.kundapura@intel.com/ , callbacks are getting called for both NULL pmd and qat
> pmd.
> 
> Acked-by: Ganapati Kundapura <ganapati.kundapura at intel.com>
Applied to dpdk-next-crypto
Fixed a couple of minor typos in comments.