core/sched: uncrustify sched_cb declaration
core/sched: uncrustify sched_cb declaration

this is a change out of this PR scope to reduce
the number of uncrustify complains for future edits

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