virtio-scsi: add ioeventfd support

Probably due to bad merge months ago, virtio-scsi-pci did not have
ioeventfd support.  Fix this and enable it by default, as is the
case for other virtio-pci devices.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/virtio-pci.c

@@ -1040,6 +1040,7 @@ static int virtio_scsi_exit_pci(PCIDevice *pci_dev)
 }
 
 static Property virtio_scsi_properties[] = {
+    DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags, VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
     DEFINE_VIRTIO_SCSI_PROPERTIES(VirtIOPCIProxy, host_features, scsi),
     DEFINE_PROP_END_OF_LIST(),