aux-to-i2c-bridge: don't allow user to create one

This device is private and is created once per aux-bus.
So don't allow the user to create one from command-line.

Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: KONRAD Frederic <frederic.konrad@adacore.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

hw/misc/auxbus.c

@@ -210,6 +210,16 @@ struct AUXTOI2CState {
     I2CBus *i2c_bus;
 };
 
+static void aux_bridge_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    /* This device is private and is created only once for each
+     * aux-bus in aux_init_bus(..). So don't allow the user to add one.
+     */
+    dc->user_creatable = false;
+}
+
 static void aux_bridge_init(Object *obj)
 {
     AUXTOI2CState *s = AUXTOI2C(obj);
@@ -225,6 +235,7 @@ static inline I2CBus *aux_bridge_get_i2c_bus(AUXTOI2CState *bridge)
 static const TypeInfo aux_to_i2c_type_info = {
     .name = TYPE_AUXTOI2C,
     .parent = TYPE_DEVICE,
+    .class_init = aux_bridge_class_init,
     .instance_size = sizeof(AUXTOI2CState),
     .instance_init = aux_bridge_init
 };