crypto/aesni_gcm: do crypto op in dequeue function

crypto/aesni_gcm: do crypto op in dequeue function

There is bug when more crypto ops are enqueued than dequeued.
The return value is not checked when trying to enqueue the
processed crypto op into the internal ring, which in the case of being
full will results in crypto ops and mbufs being leaked.
The issue is more obvious with different cores doing enqueue/dequeue.

This patch moves the crypto operation to the dequeue function which
fixes the above issue without having to check for the number of free
entries in the ring.

Fixes: eec136f3c54f ("aesni_gcm: add driver for AES-GCM crypto operations")

Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
Acked-by: Declan Doherty <declan.doherty@intel.com>