hw/isa/isa-superio: Fix IDE controller realization

When realizing a Super I/O with IDE controller [*], we get:

  qom/object.c:1684: object_property_try_add_child: Assertion `!child->parent' failed.
  Aborted (core dumped)

This is because the device is already realized when we try to
add the QOM property to the parent. Fix by realizing *after*
adding the QOM relationship.

[*] Set ISASuperIOClass::ide.count = N with N not zero
    (no such thing currently exists; the bug is latent)

Fixes: e5084306 ("hw/isa/superio: Make the components QOM children")
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200721124516.9602-1-f4bug@amsat.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

hw/isa/isa-superio.c

@@ -158,8 +158,8 @@ static void isa_superio_realize(DeviceState *dev, Error **errp)
         if (k->ide.get_irq) {
             qdev_prop_set_uint32(d, "irq", k->ide.get_irq(sio, 0));
         }
-        isa_realize_and_unref(isa, bus, &error_fatal);
         object_property_add_child(OBJECT(sio), "isa-ide", OBJECT(isa));
+        isa_realize_and_unref(isa, bus, &error_fatal);
         sio->ide = isa;
         trace_superio_create_ide(0,
                                  k->ide.get_iobase ?