boards/stm32f469i-disco: LEDX_ON LEDX_OFF mismatch fix
boards/stm32f469i-disco: LEDX_ON LEDX_OFF mismatch fix

kaspar030/RIOT,kaspar030/RIOT,kYc0o/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,jasonatran/RIOT,miri64/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,ant9000/RIOT,kaspar030/RIOT,kaspar030/RIOT,kaspar030/RIOT,miri64/RIOT,kYc0o/RIOT,miri64/RIOT,RIOT-OS/RIOT,miri64/RIOT,kYc0o/RIOT,miri64/RIOT,ant9000/RIOT,ant9000/RIOT,jasonatran/RIOT,jasonatran/RIOT,ant9000/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,ant9000/RIOT