TYRA Banks has advised her porn-star lookalike, Tyra Banxxx, to quit the business and find a more respectable job. But her campaign backfired. Banxxx just shot a new hard-core video that cheekily parodies Banks called "America's Next Top Porn Model," in which women compete by performing sex acts. Banxxx tells avn.com, "I love this business and I'm not going to leave it, and I'm not going to change my name