ixd: add devlink support

Enable initial support for the devlink interface with the ixd driver. The
ixd hardware is a single function PCIe device. So, the PCIe adapter gets
its own devlink instance to manage device-wide resources or configuration.

$ devlink dev show
pci/0000:83:00.6

$ devlink dev info pci/0000:83:00.6
pci/0000:83:00.6:
  driver ixd
  serial_number 00-a0-c9-ff-ff-23-45-67
  versions:
      fixed:
        device.type MEV
      running:
        virtchnl 2.0

Signed-off-by: Amritha Nambiar <amritha.nambiar@intel.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Tested-by: Bharath R <Bharath.r@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>