Bobby Cannavale’s dream of working with Al Pacino is coming true with an upcoming revival of David Mamet’s “Glengarry Glen Ross.” Cannavale told us the project took root when the actors were seated next to each other at the Tonys last year, and Pacino then went to see Cannavale in “The Motherf**ker With the Hat.” “He came backstage and stayed for close to two hours just talking with me, and said, ‘We should do something together,’ ” Cannavale told us Monday at a benefit for the Trevor Project at Chelsea Piers. “It worked out perfectly. And all I had to do was act,” said Cannavale, who’s taking on the role of Ricky Roma, which Pacino played in Mamet’s 1992 film version starring Jack Lemmon, Alec Baldwin and Kevin Spacey. (Note for Mamet aficionados: Pacino’s playing Lemmon’s role of Shelley Levene.) Cannvale said he’s seen the movie “several times,” but he won’t be checking it out again before performances begin at the Gerald Schoenfeld Theatre this fall, so he can “approach it freshly” with Pacino. Even before the collaboration, Cannavale says he’s always used Pacino as motivation: “I’ve pretty much spent every show I’ve ever done having this ritual where I walk to the theater, and in my head, right before I walk in, I say, ‘Al Pacino is [in the audience] tonight.’ ”