app/testpmd: fix NUMA structures initialization

Previous numa_support = 0 by default, it need to add --numa to testpmd
command line to enable numa, so port_numa and ring_numa were initialized
at function launch_args_parse(), now testpmd change numa_support = 1 as
default, so port_numa and ring_numa also need to initialize by default,
otherwise port->socket_id will be probed to wrong value.

Fixes: 999b2ee0fe45 ("app/testpmd: enable NUMA support by default")

Signed-off-by: Yulong Pei <yulong.pei@intel.com>
Acked-by: Jingjing Wu <jingjing.wu@intel.com>