virtchnl: Add virtchl structures to support queue channels

This patch defines new structs in support of the virtchannel message
that the VF sends to the PF to create a queue channel specified by the
user via tc tool.

Signed-off-by: Harshitha Ramamurthy <harshitha.ramamurthy@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>