[X86] Remove 128/256-bit masked pmaddubsw and pmaddwd intrinsics. Replace 512-bit masked intrinsic with unmasked intrinsic and a select.

The 128/256-bit versions were no longer used by clang. It uses the legacy SSE/AVX2 version and a select. The 512-bit was changed to the same for consistency.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329774 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed