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: NEric Auger <eric.auger@linaro.org>
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>