pci: allow 32-bit PCI IO accesses to pass through the PCI bridge

Whilst the underlying PCI bridge implementation supports 32-bit PCI IO
accesses, unfortunately they are truncated at the legacy 64K limit.
Signed-off-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/pci/pci_bridge.c

@@ -379,7 +379,8 @@ void pci_bridge_initfn(PCIDevice *dev, const char *typename)
     sec_bus->address_space_mem = &br->address_space_mem;
     memory_region_init(&br->address_space_mem, OBJECT(br), "pci_bridge_pci", UINT64_MAX);
     sec_bus->address_space_io = &br->address_space_io;
-    memory_region_init(&br->address_space_io, OBJECT(br), "pci_bridge_io", 65536);
+    memory_region_init(&br->address_space_io, OBJECT(br), "pci_bridge_io",
+                       UINT32_MAX);
     br->windows = pci_bridge_region_init(br);
     QLIST_INIT(&sec_bus->child);
     QLIST_INSERT_HEAD(&parent->child, sec_bus, sibling);