vfio/pci: remove vfio_pci_nvlink2

This driver never had any open userspace (which for VFIO would include
VM kernel drivers) that use it, and thus should never have been added
by our normal userspace ABI rules.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Message-Id: <20210326061311.1497642-2-hch@lst.de>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>