“Don’t call it a comeback, he been here for years, rocking his peers, putting ’em in fear, making tears rain down like a monsoon, explosions overpowerin’, over the competition LL Cool J is towering. LL Cool J — stands for Ladies Love Cool J.” On the eve of the premiere of his new XM “Theme Time Radio Hour” (which premieres Wednesday,) Bob Dylan shares some of his early show playlists (organized around themes such as the weather, mothers, drinking, and cars) and his on-air comments about some favorite selections.