Geraldo Rivera says he's having a devil of a time with NBC over his upcoming special on satanism. The television journalist said last week that he is so unhappy with the network's censors that he may broadcast blank pictures Tuesday (8 p.m. on Channels 4, 36 and 39) rather than make any more cuts in his show, "Devil Worship: Exposing Satan's Underground." He had hoped to include graphic descriptions of murders and other satanic rituals in the two-hour program. "NBC says, for example, that a lot of the things that are portrayed are too rough to take. 'Too rough for whom to take?' is our response," he said. NBC spokeswoman Rosemary Keenan said talks between Rivera and network censors were continuing. "We're hoping to come to a mutual decision," she said.