qom: Add object_property_set_default_list()

This function provides a default for properties that are accessed using
the list visitor interface. The default is always an empty list.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-ID: <20231109174240.72376-10-kwolf@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>