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

- Fix formatting issue due to hyphenated terms at line breaks.
- Fix typo

This patch was made by Craig Flores

Differential Revision: https://reviews.llvm.org/D41520


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@321671 91177308-0d34-0410-b5e6-96231b3b80d8