hw/usb: Constify VMStateDescription

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210313171150.2122409-4-f4bug@amsat.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2 files changed