[AVX-512] Remove duplicate CodeGenOnly patterns for scalar register broadcast. We can use COPY_TO_REGCLASS like AVX does.

This causes stack spill slots be oversized sometimes, but the same should already be happening with AVX.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293464 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed