Instead of having an option to build the gvt code into the main i915
module, just move it into the kvmgt.ko module.  This only requires
a new struct with three entries that the KVMGT modules needs to register
with the main i915 module, and a proper list of GVT-enabled devices
instead of global device pointer.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220411141403.86980-7-hch@lst.deReviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>