LOS ANGELES — Mohamed Diawara’s first NBA dunk was a poster. The Knicks rookie highlighted an otherwise dreary Knicks loss Monday with a dribble through the Clippers defense before a one-handed jam over fellow Frenchman Nic Batum. It occurred late in the third quarter and ignited a pro-Knicks crowd at the Intuit Dome, but the visitors couldn’t complete a comeback and fell amid a rash of turnovers, 126-118 . “I was just driving and dunked the ball and fortunately (Batum) was there,” Diawara, who