igb: add pf side of VMDq support

Add the pf portion of vmdq support.  This provides enough support so that
VMDq is enabled, and the pf is functional without enabling vfs.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>