By Pete Schroeder WASHINGTON (Reuters) -A U.S. bank regulator approved new final rules aimed at easing leverage requirements for banks, requiring firms to set ​aside less capital as a cushion against losses of low-risk assets. The Federal Deposit Insurance ‌Corporation approved the new final rules for the "enhanced supplementary leverage ratio," and other bank regulators are expected to ‌similarly approve the new rules, which were first proposed in June. An FDIC staff memo estimated the new rules would ...