Sprint Nextel Corp. suitor SoftBank Corp. has put a limit on how high the carrier’s current $2.1 billion bid for Clearwire Corp. can go, even as Clearwire shareholders clamor to increase the per-share price, Reuters reports. Overland Park-based Sprint (NYSE: S) said Thursday that it would buy all of Clearwire (Nasdaq: CLWR) that it didn’t already own. Analysts expressed skepticism, saying the low per-share price could hang up the deal. The deal puts much at stake for Sprint. Should it succeed,…