vfio-pci/nvlink2: Fix potential VMA leak

If vfio_pci_register_dev_region() fails then we should rollback
previous changes, ie. unmap the ATSD registers.

Fixes: 7f928917 ("vfio_pci: Add NVIDIA GV100GL [Tesla V100 SXM2] subdriver")
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/pci/vfio_pci_nvlink2.c

@@ -472,6 +472,8 @@ int vfio_pci_ibm_npu2_init(struct vfio_pci_device *vdev)
 	return 0;
 
 free_exit:
+	if (data->base)
+		memunmap(data->base);
 	kfree(data);
 
 	return ret;