[DOXYGEN] Fix doxygen and content issues in xmmintrin.h

- Fix inaccurate instruction listings.
- Fix small issues in _mm_getcsr and _mm_setcsr.
- Fix description of NaN handling in comparison intrinsics.
- Fix inaccurate description of _mm_movemask_pi8.
- Fix inaccurate instruction mappings.
- Fix typos.
- Clarify wording on some descriptions.
- Fix bit ranges in return value.
- Fix typo in _mm_move_ms intrinsic instruction since it operates on singe-precision values, not double.
- This patch was made by Craig Flores

Differential Revision: https://reviews.llvm.org/D41523

llvm-svn: 322778