examples/eventdev: fix run forever with -n option
examples/eventdev: fix run forever with -n option

During the refactoring of the sample app to be more generic, the
option to set -n0 and process a huge number of packets was lost.
This commit re-adds -n0, and will process INT64_MAX number of packets.

Fixes: adb5d5486c39 ("examples/eventdev_pipeline_sw_pmd: add sample app")

Signed-off-by: Harry van Haaren <b9ad04ed670c22cfa7f5f9ab17e311ca85d11a76@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk