drm/xe: Add device flag to indicate SR-IOV support

drm/xe: Add device flag to indicate SR-IOV support

The Single Root I/O Virtualization (SR-IOV) extension to
the PCI Express (PCIe) specification suite is supported
starting from 12th generation of Intel Graphics processors.

Add a device flag that we will use to enable SR-IOV specific
code paths and to indicate our readiness to support SR-IOV.

We will enable this flag for the specific platforms once all
required changes and additions will be ready and merged.

Bspec: 52391
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20231115073804.1861-1-michal.wajdeczko@intel.com
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>