Mk20Clock: Cosmetic fix (clear overflow on init).
Mk20Clock: Cosmetic fix (clear overflow on init).

ambrop72/aprinter,johnkingsley/aprinter,ambrop72/aprinter,ambrop72/aprinter,johnkingsley/aprinter,fixator/aprinter,ambrop72/aprinter,fixator/aprinter,johnkingsley/aprinter,fixator/aprinter,johnkingsley/aprinter,ambrop72/aprinter,ambrop72/aprinter,fixator/aprinter,johnkingsley/aprinter,johnkingsley/aprinter,fixator/aprinter,johnkingsley/aprinter,fixator/aprinter,ambrop72/aprinter