PHILADELPHIA — “Let’s go Knicks,” they roared early as the 3-pointers fell like an avalanche. “Deuce,” they bellowed after every one of Miles McBride’s seven 3-pointers. “Knicks in four,” they chanted as the road team piled it on. Technically, Game 4 of the Eastern Conference semifinals was a road game for the Knicks. It just didn’t feel anything like one, fans of the orange and blue taking over Xfinity Mobile Arena to watch their Knicks complete a four-game sweep of the host 76ers with a 144-114 decimation on Mother’s Day . “I used to think Philly was a sports town,” Josh Hart said with a wry smile. “I don’t know if it is anymore.” It was a Knicks town this weekend. There was a strong contingent of Knicks fans for Friday night’s Game 3, but they were mostly drowned out by the 76ers supporters until the game was out of reach. Knicks fans celebrate at Xfinity Mobile Arena on May 10. Charles Wenzelberg / New York Post Sunday was different. Sunday, they owned the building. Sunday, they made it their home.…