RDMA/irdma: Add support for DSCP

Add DSCP support for the Intel Ethernet 800 Series devices.  Setup VSI
DSCP info when PCI driver indicates DSCP mode during driver probe or as
notification event.

Link: https://lore.kernel.org/r/20220202191921.1638-4-shiraz.saleem@intel.com


Signed-off-by: Mustafa Ismail <mustafa.ismail@intel.com>
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>