Let's hear it for Deniece Williams. By the time of her debut album in 1976, the resilient singer with the remarkable range had already recorded a Northern Soul favorite ("I'm Walking Away" on the small Lock Records label), performed with Minnie Riperton and Roberta Flack, and been a member of Stevie Wonder's versatile backing group Wonderlove. This is Niecy, on Columbia Records, was produced by Maurice White of Earth, Wind & Fire and Charles Stepney of Chess Records fame, and their