spapr: Direct all PCI hotplug to host bridge, rather than P2P bridge

A P2P bridge will attempt to handle the hotplug with SHPC, which doesn't
work in the PAPR environment.  Instead we want to direct all PCI hotplug
actions to the PAPR specific host bridge which will use the PAPR hotplug
mechanism.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

hw/ppc/spapr.c

@@ -4094,6 +4094,17 @@ static HotplugHandler *spapr_get_hotplug_handler(MachineState *machine,
         object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_PCI_HOST_BRIDGE)) {
         return HOTPLUG_HANDLER(machine);
     }
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
+        PCIDevice *pcidev = PCI_DEVICE(dev);
+        PCIBus *root = pci_device_root_bus(pcidev);
+        SpaprPhbState *phb =
+            (SpaprPhbState *)object_dynamic_cast(OBJECT(BUS(root)->parent),
+                                                 TYPE_SPAPR_PCI_HOST_BRIDGE);
+
+        if (phb) {
+            return HOTPLUG_HANDLER(phb);
+        }
+    }
     return NULL;
 }