virtio-balloon-pci: switch to the new API.

virtio-balloon-pci: switch to the new API.

Here the virtio-balloon-pci is modified for the new API. The device
virtio-balloon-pci extends virtio-pci. It creates and connects a
virtio-balloon during the init. The properties are not changed.

Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Message-id: 1364377755-15508-3-git-send-email-fred.konrad@greensocs.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>