Sony’s PlayStation Portable is an impressive little gadget, but it won’t give the company any advantage in the battle for the living room, Microsoft’s top Xbox executive said Wednesday. Speaking at a Churchill Club event, Robbie Bach, senior vice president and chief Xbox officer for Microsoft, gave Sony credit for designing a slick handheld game player. But he said whatever success the PSP achieves is unlikely to boost sales for the next version of Sony’s PlayStation living room game console.