Merge remote-tracking branch 'sstabellini/xen-pt' into staging

Merge remote-tracking branch 'sstabellini/xen-pt' into staging

* sstabellini/xen-pt:
  Introduce Xen PCI Passthrough, MSI
  Introduce apic-msidef.h
  Introduce Xen PCI Passthrough, PCI config space helpers
  Introduce Xen PCI Passthrough, qdevice
  qdev-properties: Introduce pci-host-devaddr.
  pci.c: Add opaque argument to pci_for_each_device.
  Introduce XenHostPCIDevice to access a pci device on the host.
  configure: Introduce --enable-xen-pci-passthrough.
  pci_ids: Add INTEL_82599_SFP_VF id.