pci: remove PCIBus::config_reg.

PCIBus::config_reg isn't used anymore, so remove it.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/pci.c

@@ -41,7 +41,6 @@ struct PCIBus {
     pci_set_irq_fn set_irq;
     pci_map_irq_fn map_irq;
     pci_hotplug_fn hotplug;
-    uint32_t config_reg; /* XXX: suppress */
     void *irq_opaque;
     PCIDevice *devices[256];
     PCIDevice *parent_dev;