virtio: Remove duplicate macro definition for max. virtqueues, bump up the max VIRTIO_PCI_QUEUE_MAX is redefined in hw/virtio.c. Let's just keep it in hw/virtio.h. Also, bump up the value of the maximum allowed virtqueues to 64. This is in preparation to allow multiple ports per virtio-console device. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>