pci: Q35, Root Ports, and Switches create PCI Express buses

Convert q35, ioh3420, xio3130_upstream, and xio3130_downstream to
use the new TYPE_PCIE_BUS.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/hw/ioh3420.c b/hw/ioh3420.c
index 74d84d4..5cff61e 100644
--- a/hw/ioh3420.c
+++ b/hw/ioh3420.c
@@ -97,7 +97,7 @@
     PCIESlot *s = DO_UPCAST(PCIESlot, port, p);
     int rc;
 
-    rc = pci_bridge_initfn(d, TYPE_PCI_BUS);
+    rc = pci_bridge_initfn(d, TYPE_PCIE_BUS);
     if (rc < 0) {
         return rc;
     }