examples/vmdq_dcb: support X710

examples/vmdq_dcb: support X710

Currently, the example vmdq_dcb only works on Intel(R) 82599 NICs.
This patch extends this sample to make it work both on Intel(R) 82599
and X710/XL710 NICs by making the following changes:
  1. add VMDQ base queue checking to avoid forwarding on PF queues.
  2. assign each VMDQ pool to a MAC address.
  3. add more arguments (nb-tcs, enable-rss) to change the default
     setting
  4. extend the max number of queues from 128 to 1024.
This patch also reworks the user guide for the vmdq_dcb sample.

Signed-off-by: Jingjing Wu <jingjing.wu@intel.com>
Acked-by: Helin Zhang <helin.zhang@intel.com>