T-Mobile CEO John Legere may want to make sure his résumé is up to date. Unnamed sources tell Reuters that Sprint parent company SoftBank is already in talks to buy a majority stake T-Mobile US from Deutsche Telekom for $20 billion, a little less than the $21.6 billion that SoftBank paid for Sprint. However, just because SoftBank makes a bid for T-Mobile that doesn’t mean U.S. regulators will allow the deal to go through, especially if they conclude that it will hurt competition in the wireless space. What’s more, a proposed Sprint-T-Mobile merger would come during a time when T-Mobile has really started making waves in the wireless industry with its aggressive “uncarrier” moves that have put pressure on incumbent carriers to