If testpmd is invoked with portmask option like below, segmentation
fault will occur. This patch fixes the issue.
Reported-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Signed-off-by: Tetsuya Mukawa <mukawa@igel.co.jp>
Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>