[PATCH] [TargetInfo] Move LinkerInputFile to TargetInfo and rename more specific name

[Rui Ueyama]

  Sorry the last change comment was wrong. Instead of keeping LinkerInputFile, I directly use SimpleFile. It's because the class beaome too simple to be a class. I think SimpleFile will serves the purpose you described.

http://llvm-reviews.chandlerc.com/D1016