tools: rinaperf: use data_flow_ready condition variable only on demand
tools: rinaperf: use data_flow_ready condition variable only on demand

autrimpo/rlite,vmaffione/rlite,vmaffione/rlite,vmaffione/rlite,autrimpo/rlite,autrimpo/rlite,vmaffione/rlite,autrimpo/rlite