For some reason the vfio_mdev shim mdev_driver has its own module and
kconfig. As the next patch requires access to it from mdev.ko merge the
two modules together and remove VFIO_MDEV_DEVICE.

A later patch deletes this driver entirely.
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NKirti Wankhede <kwankhede@nvidia.com>
Link: https://lore.kernel.org/r/20210617142218.1877096-7-hch@lst.deSigned-off-by: NAlex Williamson <alex.williamson@redhat.com>