'static build:' must display value of CONFIG_STATIC rather than value of
CONFIG_TOOLS.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200917140700.673171-1-lvivier@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>