ztimer/xtimer_compat: implement trivial functions
ztimer/xtimer_compat: implement trivial functions

xtimer_ticks64_t / xtimer_ticks32_t is no longer a struct, so these are
even more trivial than on xtimer.

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