dpif-netdev: log port/core affinity

dpif-netdev: log port/core affinity

When using multiple PMDs and numerous ports, a performance gain
may be achieved in some use cases by pinning a PMD/port to a
particular (set of) core(s).

This patch provides a summary of the switch's port/core affinities
each time that the status of the switch's ports is modified.
Based on this information, a user may determine what affinity
modifications are required to optimise performance for their
particular use case.

Signed-off-by: Mark Kavanagh <mark.b.kavanagh@intel.com>
Signed-off-by: Wojciech Andralojc <wojciechx.andralojc@intel.com>
Acked-by: Flavio Leitner <fbl@redhat.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>