This structure is going to be shared by VFIOPCIDevice and
VFIOPlatformDevice. VFIOBAR includes it.
vfio_eoi becomes an ops of VFIODevice specialized by parent device.
This makes possible to transform vfio_bar_write/read into generic
vfio_region_write/read that will be used by VFIOPlatformDevice too.
vfio_mmap_bar becomes vfio_map_region
Signed-off-by: Eric Auger <eric.auger@linaro.org> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>