MIPS64: Clean-up intrinsics code

- Wrap lines longer that 100 characters.
- Fix return type in comments for various Long intrinsics.
- Add Location::OutputOverlap parameter to CreateFPToFP() function;
  wrong value was being used for floor()/ceil() intrinsics.

Change-Id: I998b647e1c20521a72da89cfe2d5a4c27e3ab85c