pipeline: fix argument check
pipeline: fix argument check

Coverity issue: 362789
Fixes: 3ca60ceed7 ("pipeline: add SWX pipeline specification file")

Signed-off-by: Cristian Dumitrescu <25468b8a3698eeb3c368247f8635924bb4a1ce2c@intel.com>

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