hw/ppc/spapr_vio: Realize SPAPR_VIO_BRIDGE device before accessing it

qbus_new() should not be called on unrealized device.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20231019131647.19690-2-philmd@linaro.org>

hw/ppc/spapr_vio.c

@@ -574,13 +574,14 @@ SpaprVioBus *spapr_vio_bus_init(void)
 
     /* Create bridge device */
     dev = qdev_new(TYPE_SPAPR_VIO_BRIDGE);
-    sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
 
     /* Create bus on bridge device */
     qbus = qbus_new(TYPE_SPAPR_VIO_BUS, dev, "spapr-vio");
     bus = SPAPR_VIO_BUS(qbus);
     bus->next_reg = SPAPR_VIO_REG_BASE;
 
+    sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
+
     /* hcall-vio */
     spapr_register_hypercall(H_VIO_SIGNAL, h_vio_signal);