PHOENIX — Lakers coach Phil Jackson wasn’t too happy to hear Andrew Bynum say he was looking ahead to playing the Boston Celtics in the NBA Finals next month. Said Jackson before Game 3 tonight: “It was a moment we’d call a brain (cramp) in our business,He wasn’t thinking very clearly right then. … We’re not thinking ahead. If we do, we’re going to end up coming back here (for Game 6).”