vfio: Remove migration protocol v1 documentation

v1 was never implemented and is replaced by v2.

The old uAPI documentation is removed from the header file.

The old uAPI definitions are still kept in the header file to ease
transition for userspace copying these headers. They will be fully
removed down the road.

Link: https://lore.kernel.org/all/20220224142024.147653-12-yishaih@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>