* Garrulous actor already in spotlight over tax row * Drink driving case will now go to full trial * Could face up to two years in prison By Alexandria Sage PARIS, Jan 8 (Reuters) - French film star Gerard Depardieu failed to show up in court to face drink driving charges on Tuesday because he was preparing to play disgraced former IMF chief Dominique Strauss-Kahn in a film, his lawyer said.