hw/virtio/vhost-user: don't use uninitialized variable

hw/virtio/vhost-user: don't use uninitialized variable

Variable `vdev` in `struct vhost_dev` will not be ready
until start the device, so let's not use it for the error
output here.

Fixes: 5653493 ("hw/virtio/vhost-user: don't suppress F_CONFIG when supported")
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Message-Id: <20220525125540.50979-1-changpeng.liu@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Fixes: 5653493 ("hw/virtio/vhost-user: don't suppress F_CONFIG when supported")
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Fixes: 5653493 ("hw/virtio/vhost-user: don't suppress F_CONFIG when supported")
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>