[Hexagon] Update Hexagon ArchEnum and sync some downstream changes(NFC)

Differential Revision: https://reviews.llvm.org/D38850


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316099 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed