ppc_prep: fix pci config space initialization

Use data_mem for the data mmio region, not conf_mem.
Signed-off-by: NAvi Kivity <avi@redhat.com>

hw/prep_pci.c

@@ -130,7 +130,7 @@ PCIBus *pci_prep_init(qemu_irq *pic,
     memory_region_add_subregion(address_space_io, 0xcf8, &s->conf_mem);
     sysbus_init_ioports(&s->busdev, 0xcf8, 1);
 
-    memory_region_init_io(&s->conf_mem, &pci_host_data_be_ops, s,
+    memory_region_init_io(&s->data_mem, &pci_host_data_be_ops, s,
                           "pci-conf-data", 1);
     memory_region_add_subregion(address_space_io, 0xcfc, &s->data_mem);
     sysbus_init_ioports(&s->busdev, 0xcfc, 1);