vfio/xe: Add device specific vfio_pci driver variant for Intel graphics

vfio/xe: Add device specific vfio_pci driver variant for Intel graphics

In addition to generic VFIO PCI functionality, the driver implements
VFIO migration uAPI, allowing userspace to enable migration for Intel
Graphics SR-IOV Virtual Functions.
The driver binds to VF device and uses API exposed by Xe driver to
transfer the VF migration data under the control of PF device.

Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Alex Williamson <alex@shazbot.org>
Link: https://patch.msgid.link/20251127093934.1462188-5-michal.winiarski@intel.com
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>