pds_core: set up the VIF definitions and defaults

The Virtual Interfaces (VIFs) supported by the DSC's
configuration (vDPA, Eth, RDMA, etc) are reported in the
dev_ident struct and made visible in debugfs.  At this point
only vDPA is supported in this driver so we only setup
devices for that feature.

Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>