[Hexagon] Adding encoding bits for add opcode.
Adding llvm-mc tests.
Removing unit tests.

http://reviews.llvm.org/D5624

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220427 91177308-0d34-0410-b5e6-96231b3b80d8
14 files changed