PMD features matrix

Hi,

Reminder:
We have a tool to monitor the PMD features implementations:
	http://dpdk.org/doc/guides/nics/overview.html#id1
It may be used for various important needs, and must be updated
when the code change.

There are still some drivers not filled in this matrix
(null, af_packet, xenvirt and bonding).
Please check doc/guides/nics/features/ and fill it.

Thanks