MIDDLESBROUGH, England (Reuters) – Chelsea continued to make light of their off-pitch turmoil with impressive displays on it as they reached the FA Cup semi-finals with a 2-0 victory at Middlesbrough on Saturday. First-half goals by Romelu Lukaku and Hakim Ziyech knocked the stuffing out of second-tier Middlesbrough who had eliminated Manchester United and Tottenham Hotspur in previous rounds. Lukaku tapped in Mason Mount’s low cross after 15 minutes before Ziyech fired home 16 minutes later. Middlesbrough were given raucous support inside the Riverside Stadium but never really looked capable …