KFC and Pizza Hut parent Yum Brands reported a bigger-than-expected fall in same-store sales for the second quarter as sticky inflation discouraged lower-income Americans from spending on dining out.Same-store sales at the company’s KFC division fell 5% in the United States in the second quarter, compared with a 7% decline in the prior quarter, while Pizza Hut reported a decline of 1%, Yum said Tuesday.Like its peers in the fast-food industry, Yum, which also owns Taco Bell, has been investing in loyalty pr ...