ARLINGTON, Texas — Dak Prescott and the Dallas Cowboys didn’t have to worry about the NFC East title anymore once they kicked off against Washington. So they took care of the star quarterback’s slump instead. Prescott threw four touchdown passes, DeMarcus Lawrence returned an interception for a score and the Dallas Cowboys celebrated their clinching of the division crown with a 56-14 rout of Washington on Sunday night. The Cowboys (11-4) tied the franchise record for points in a first half while taking a 42-7 lead and frustrating Washington to the point that defensive tackles Jonathan Allen and Daron Payne scuffled on the sideline. Dallas didn’t need to win to add the division title to the playoff berth that was sealed with San Francisco’s loss to Tennessee three nights earlier. Las Vegas’ 17-13 victory over Denver took care of that about an hour before kickoff, giving the Cowboys a tiebreaker over Philadelphia. Prescott and company didn’t seem to care, and now the Eagles can’t ...