cpu/cc430: rtc: remove dead code
cpu/cc430: rtc: remove dead code

The commented-out block does provide no value and is confusing
when using `grep`.

OlegHahm/RIOT,smlng/RIOT,smlng/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,basilfx/RIOT,miri64/RIOT,OTAkeys/RIOT,yogo1212/RIOT,jasonatran/RIOT,OlegHahm/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,authmillenon/RIOT,miri64/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,yogo1212/RIOT,smlng/RIOT,smlng/RIOT,ant9000/RIOT,miri64/RIOT,RIOT-OS/RIOT,yogo1212/RIOT,kaspar030/RIOT,kYc0o/RIOT,basilfx/RIOT,kYc0o/RIOT,ant9000/RIOT,yogo1212/RIOT,OlegHahm/RIOT,OlegHahm/RIOT,jasonatran/RIOT,OTAkeys/RIOT,kYc0o/RIOT,kYc0o/RIOT,authmillenon/RIOT,miri64/RIOT,smlng/RIOT,miri64/RIOT,kYc0o/RIOT,basilfx/RIOT,kaspar030/RIOT,yogo1212/RIOT,kaspar030/RIOT,authmillenon/RIOT,jasonatran/RIOT,ant9000/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,authmillenon/RIOT,yogo1212/RIOT,OTAkeys/RIOT,OTAkeys/RIOT,basilfx/RIOT,ant9000/RIOT,basilfx/RIOT,jasonatran/RIOT,authmillenon/RIOT,jasonatran/RIOT,ant9000/RIOT