[clang] [X86][AVX10.2] Add missing _mm_cvtts_ss/sd* intrinsics (PR #211185)

[Simon Pilgrim via cfe-commits]

https://github.com/RKSimon approved this pull request.

LGTM - at some point in the future it'd be good to add doxygen comments

https://github.com/llvm/llvm-project/pull/211185