[DPDK] Add ability to set pmd_rxq_affinity for dpdk interfaces

This enables a more fine tuned dpdk for better performance.
More details on pmd-rxq-affinity config:
http://docs.openvswitch.org/en/latest/howto/dpdk/

Change-Id: I630c6af94ff733619fb175f522fc515984862ff6
2 files changed