app/crypto-perf: fix crypto operation resubmission

app/crypto-perf: fix crypto operation resubmission

This patch fixes the crypto operation resubmission problem in crypto
perferformance test. Originally, when needed crypto ops amount is
smaller than the enqueued crypto ops in the last round, one or more
processed crypto operations will be re-enqueued.

Fixes: f8be1786b1b8 ("app/crypto-perf: introduce performance test application")
Cc: stable@dpdk.org
Signed-off-by: Fan Zhang <roy.fan.zhang@intel.com>
Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>