[Hexagon] Add a "generic" cpu

Add the generic processor for Hexagon so that it can be used
with 3rd party programs that create a back-end with the
"generic" CPU. This patch also enables the JIT for Hexagon.

Differential Revision: https://reviews.llvm.org/D48571



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335641 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed