hpet: Remove user_creatable flag

hpet needs to be mapped and wired by the board code and won't
work with -device. Remove the user_creatable flag from the device
class.

Cc: Marcel Apfelbaum <marcel@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Marcel Apfelbaum <marcel@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20170503203604.31462-18-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

hw/timer/hpet.c

@@ -771,11 +771,6 @@ static void hpet_device_class_init(ObjectClass *klass, void *data)
     dc->reset = hpet_reset;
     dc->vmsd = &vmstate_hpet;
     dc->props = hpet_device_properties;
-    /*
-     * FIXME: Set only because we are not sure yet if this device
-     * will be outside the q35 sysbus whitelist.
-     */
-    dc->user_creatable = true;
 }
 
 static const TypeInfo hpet_device_info = {