(Reuters) – UK Prime Minister Boris Johnson has joined a final push to convince SoftBank Group Corp-backed chip designer Arm to list in London, the Financial Times reported on Monday, citing people familiar with the matter. Johnson has written to SoftBank executives as part of the last-ditch effort, the report said, adding that ministers and executives from the London Stock Exchange (LSE) are trying to persuade the Japanese conglomerate to rethink their preference for listing in New York. Arm, the LSE and SoftBank did not immediately respond to Reuters’ requests for comment, while the prime mi…