By Wilton Jackson The five-time NBA champion says the Philadelphia star has to be better in performances with the season on the line. James Harden’s dismal performance against the Heat in Game 6 of the Eastern Conference semifinals sparked a continuing conversation about his ability to perform when it matters most. Harden, who finished with 11 points in Philadelphia’s season-ending loss to Miami on Thursday, attempted only two shots in the second half of the game. Five-time NBA champion Magic Johnson called out Harden for his dreadful performance and one that lacked effort. “James Harden, in a…