U.S. regulators have collected the final vote to approve the merger of Sprint and SoftBank, sources familiar with the situation said, clearing the last hurdle in the Japanese company’s drawn-out battle to take control of the No. 3 U.S. wireless provider. All three Federal Communications Commission members voted in favor of that merger as well as Sprint’s related bid to buy out the shares of wireless company Clearwire that it does not already own, said the sources who spoke anonymously because the approval has not yet been announced publicly. In filings with the FCC, Sprint, Clearwire and SoftBank had said they hoped to close both deals next Monday or Tuesday. SoftBank’s $21.6…