PCI: handle PCI->PCIe bridges as well in alloc_pdev()

It's not clear why the enumerator was omitted, as these clearly shouldn't
take the "default" path (issuing a warning). Handle them the same as
legacy and PCIe->PCI bridges.

Fixes: e7e08d86ad ("IOMMU/PCI: consolidate pdev_type() and cache its result for a given device")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Stewart Hildebrand <stewart.hildebrand@amd.com>

xen/drivers/passthrough/pci.c

@@ -351,6 +351,7 @@ static struct pci_dev *alloc_pdev(struct pci_seg *pseg, u8 bus, u8 devfn)
         unsigned long flags;
 
         case DEV_TYPE_PCIe2PCI_BRIDGE:
+        case DEV_TYPE_PCI2PCIe_BRIDGE:
         case DEV_TYPE_LEGACY_PCI_BRIDGE:
             sec_bus = pci_conf_read8(pdev->sbdf, PCI_SECONDARY_BUS);
             sub_bus = pci_conf_read8(pdev->sbdf, PCI_SUBORDINATE_BUS);