samples/pktgen: Add some helper functions

1. given a device, get its NUMA belongings
2. given a device, get its queues' irq numbers.
3. given a NUMA node, get its cpu id list.

Signed-off-by: Robert Hoo <robert.hu@intel.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>