By David Lawder NUSA DUA, Indonesia (Reuters) – With odds of a split U.S. Congress rising, Treasury Secretary Janet Yellen warned that lawmakers’ failure to raise the statutory limit on U.S. debt posed a “huge threat” to America’s credit rating and functioning of U.S. financial markets. Yellen told Reuters in an interview in New Delhi on Friday that cooperation is still possible with Republicans on some issues, but lifting the debt ceiling is a non-negotiable item. Some Republicans have threatened to use the next hike in the $31.4 trillion debt ceiling as leverage to force concessions from U.S…