virtio-crypto-pci: Tidy up virtio_crypto_pci_realize()

virtio-crypto-pci: Tidy up virtio_crypto_pci_realize()

virtio_crypto_pci_realize() continues after realization of its
"virtio-crypto-device" fails.  Only an object_property_set_link()
follows; looks harmless to me.  Tidy up anyway: return after failure,
just like virtio_rng_pci_realize() does.

Cc: "Gonglei (Arei)" <[email protected]>
Cc: Michael S. Tsirkin <[email protected]>
Signed-off-by: Markus Armbruster <[email protected]>
Reviewed-by: Eric Blake <[email protected]>
Reviewed-by: Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by: Gonglei < [email protected]>
Message-Id: <20200707160613[email protected]>