The spotlight was on Joel Embiid from the opening tip. The first “f–k Embiid” chant came immediately afterward. Several more followed. The sellout crowd at Madison Square Garden took every opportunity to scream at the Sixers’ 7-footer, complaining when he flopped or baited a defender into a ticky-tack foul, erupting after every shot that went off-target. Even as the Knicks put away Game 1 of the Eastern Conference semifinals , the crowd would not relent, letting Embiid know this was just the beginning. But unlike the intense first-round matchup two years ago — when the reigning MVP delivered a series of timely buckets, cheap shots and verbal jabs — the Knicks now may have the most impactful big man in the series.…