hw/pci: removed 'rootbus nr is 0' assumption from qmp_pci_query

Use the newer pci_bus_num to correctly get the root bus number.
Signed-off-by: NMarcel Apfelbaum <marcel@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NLaszlo Ersek <lersek@redhat.com>

hw/pci/pci.c

@@ -1594,7 +1594,8 @@ PciInfoList *qmp_query_pci(Error **errp)
 
     QLIST_FOREACH(host_bridge, &pci_host_bridges, next) {
         info = g_malloc0(sizeof(*info));
-        info->value = qmp_query_pci_bus(host_bridge->bus, 0);
+        info->value = qmp_query_pci_bus(host_bridge->bus,
+                                        pci_bus_num(host_bridge->bus));
 
         /* XXX: waiting for the qapi to support GSList */
         if (!cur_item) {