drm/i915/gvt: Use the new device life cycle helpers

Move vfio_device to the start of intel_vgpu as required by the new
helpers.

Change intel_gvt_create_vgpu() to use intel_vgpu as the first param
as other vgpu helpers do.

Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: https://lore.kernel.org/r/20220921104401.38898-9-kevin.tian@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>