[PATCH] ARM: move ARMUnwindOp.h into Support

[Saleem Abdulrasool]

  FWIW, I had the same concerns as you Logan, which is why I sent this out for review.  This is following the precedent for this set by the Windows x64 unwinding support.  I did briefly look at something like what you were thinking and found that I would rather leave that to another time (as it would be a lot more work).

http://llvm-reviews.chandlerc.com/D2494