app/testpmd: add boundary check in flow command
app/testpmd: add boundary check in flow command

There is need to add boundary for input number from commandline,
If it beyond the definition, code will return error.

Signed-off-by: Wei Zhao <55941fd0e75edbdf274af2cfac8f147525678f08@intel.com>
Reviewed-by: Ferruh Yigit <ba8734c3c506d2e3557bd4ac8fdaccd25bdb9aa7@intel.com>

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