(Reuters) -Wall Street was set to open lower on Tuesday with financial stocks dropping after Moody's overnight cut credit ratings of several small- to mid-sized U.S. banks and said it could downgrade some of the country's biggest lenders. Moody's cut the ratings of 10 lenders by one notch and placed six banking giants, including Bank of New York Mellon, US Bancorp, State Street and Truist Financial, on review for potential downgrades. Big banks Goldman Sachs and Bank of America eased 1.1% and 1.7%, respectively, in premarket trading, while Bank of New York Mellon and U.S. Banc...