With President Clinton likely to renew formal diplomatic ties with Hanoi this summer, the State Dept. is rushing to help U.S. businesses land deals in Hanoi. A lobbying boost from State, plus financing from ANZ Banking Group, helped Ellicott Machine Corp. International nail Vietnam's first capital equipment order from a U.S. company. Vietnam will purchase more than $10 million worth of dredges and spare parts from Ellicott, a Baltimore-based maker of dredging equipment. Although it's tiny, Ellicott has a big name in Vietnam, where prewar vintage Ellicott dredges are still being used.