Allows the struct to be embedded directly into device models without additional
allocation.

Suggested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230612081238.1742-3-shentey@gmail.com>
[PMD: Update MAINTAINERS entry and use SPDX license identifier]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>