Garnett is known more for trash-talking than helping out opponents, but he stopped Porzingis. “You hear the boos and KG gave me great advice,’’ Porzingis said at the Knicks’ morning shootaround in Orlando’s Amway Center. “He came up to me in the summer league and (said): ‘Use that as motivation. Just let that drive you every day when you step on the floor.’ That’s what I’m trying to do. I don’t focus on it. It’s not the only thing that drives me and it still sits inside me. I just want to prove those fans wrong, prove I could be a good player.’’