Fix layering of MachineValueType.h by moving it from CodeGen to Support

This is used by llvm tblgen as well as by LLVM Targets, so the only
common place is Support for now. (maybe we need another target for these
sorts of things - but for now I'm at least making them correct & we can
make them better if/when people have strong feelings)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328395 91177308-0d34-0410-b5e6-96231b3b80d8
74 files changed