SOUND-TRACK FEVER: David Byrne's "True Stories" album is already one of the year's most intriguing sound tracks. But now he may get stiff competition from the new MCA Records sound track to "Something Wild," a new Jonathan Demme film starring Melanie Griffith and Jeff Daniels. The sound track's single is by the Fine Young Cannibals, but the song that's getting the best advance word-of-mouth is the album's lead track, "Loco de Amor (Crazy for Love)," which was written, produced and performed by none other than--David Byrne, with a vocal assist by Latin American songstress Celia Cruz. Normally, Warner Bros. Records, which has the "True Stories" sound track, would go out of its way to prevent a rival label from promoting another Byrne song, which could hurt "True Stories' " radio play and sales (especially since the first single from "True Stories" is still climbing the charts). But Byrne and "Something Wild" director Jonathan Demme are great pals--Demme directed "Stop Making Sense," the Talking Heads' concert film, and Demme even has a scene in "Something Wild" that features his and Byrne's mothers. So while MCA can't release the Byrne track as a single or a 12-inch dance record, it is quietly pushing the song with radio programmers around the country in the hopes of getting some extra exposure for the film.