drivers/dose: make use of TIM_FLAG_SET_STOPPED
drivers/dose: make use of TIM_FLAG_SET_STOPPED

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