(Changes designation of John Clifford to COO from CEO in para 16) By Divya Rajagopal TORONTO (Reuters) -As British lender HSBC Plc explores a potential sale of its Canadian unit, lawyers and analysts say the country’s concentrated banking market could discourage big domestic banks from bidding as the government has charged the antitrust regulator to push for more competition. An HSBC deal would be the first big banking sale in a decade in Canada, one of the world’s most concentrated markets where the top six banks control about 80% of total assets, according to Reuters calculations, about doub…