Now that’s one generous tip. A regular diner at a Long Island restaurant donated her kidney to the ailing manager of the popular Italian eatery, officials said. Susanne Deegan, 55, offered the life-saving donation to her buddy David Geliashvili on the spot when he first told her and her family that he was suffering from polycystic kidney disease when they visited La Bussola in Glen Cove. “I didn’t need to think about it,” Deegan said in a statement provided by Northwell’s North Shore University