vfio: Update the kdoc for vfio_device_ops

this is missed when adding bind_iommufd/unbind_iommufd and attach_ioas.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20230209081210.141372-2-yi.l.liu@intel.com


Signed-off-by: Alex Williamson <alex.williamson@redhat.com>