vhost vdpa: fix vhost_vdpa_open error handling

We must free the vqs array in the open failure path, because
vhost_vdpa_release will not be called.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Link: https://lore.kernel.org/r/1600712588-9514-2-git-send-email-michael.christie@oracle.com


Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>