sys/ztimer/xtimer_compat: fix bug introduced in #17690
sys/ztimer/xtimer_compat: fix bug introduced in #17690

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