[AVX-512] Fix the valid immediates for the scatter/gather prefetch intrinsics.

The immediate should be 1 or 2, not 0 or 1. This was found while adding bounds checking to clang. In fact the existing clang builtin test failed if we ran it all the way to assembly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297591 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed