virtio: Drop broken and superfluous object_property_set_link()

virtio: Drop broken and superfluous object_property_set_link()

virtio_crypto_pci_realize() and copies the value of vcrypto->vdev's
property "cryptodev" to vcrypto's property:

    object_property_set_link(OBJECT(vrng), "rng", OBJECT(vrng->vdev.conf.rng),
                             NULL);

Since it does so only after realize, this always fails, but the error
is ignored.

It's actually superfluous: vcrypto's property is an alias of
vcrypto->vdev's property, created by virtio_instance_init_common().

Drop the call.

Same for virtio_ccw_crypto_realize(), virtio_rng_pci_realize(),
virtio_ccw_rng_realize().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200721121153.1128844-1-armbru@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>