A BEAMING Mike Tyson walked out of a suburban Maryland jail after serving less than a quarter of his one-year sentence for assaulting two motorists over a fender-bender. ”His release was long overdue, as far as I’m concerned,” said his attorney, Paul Kemp, said Monday. The former heavyweight champion smiled but said nothing to reporters outside the jail as he and a friend entered a nearby car where his wife, Monica, waited to take him home to change clothes before meeting with his Maryland probation officer. Tyson’s release came hours after an Indiana judge announced her decision to end Tyson’s probation for a 1992 rape conviction.