"MELI'SA MORGAN." Meli'sa Morgan. Capitol. Paul Laurence, the writer-producer of Freddie ("Rock Me Tonight") Jackson fame, ably guides Morgan through a searingly hot version of Prince's "Do Me Baby" on the singer's debut album. Sung from a female perspective, this invitation to mattress heaven may lack some of Prince's pornographic zeal, but it is equally seductive. Laurence has a real flair for this type of material, but he errs elsewhere on the LP by not encouraging Morgan to zero in on a sound that is totally her own. Morgan once toured with Chaka Khan as a backup singer, and her vocal style is almost pure Khan, particularly on cuts like the brassy "I'll Give It When I Want It" and the funk-oriented "Getting to Know You Better." Morgan is confident enough to build an album around her own compositions (the Prince cut is the only outside material). What she needs is an equally confident--and more original--singing style.