Roz Kelly, who played Fonzie’s biker girlfriend Pinky Tuscadero on “Happy Days,” has pleaded innocent to three felony firearms charges. Kelly, 56, is accused of grabbing a shotgun and shooting up her Los Angeles neighbor’s car and apartment after being awakened by a blaring car alarm. She has remained jailed on $305,000 bail since her Nov. 29 arrest. During a court appearance Monday Kelly said she has lingering medical problems from a knee injury and surgeries (unrelated to the felony charges or to her arrest). Court Commissioner Michael Duffey postponed the hearing until next week to determine whether Kelly is mentally capable of serving as her own attorney. If convicted, Kelly could face up to six years in prison or probation, prosecutors said.