Revert r321894: it requires a part of another commit that is not ready yet

Commit message:
[Hexagon] Add patterns for sext_inreg of HVX vector types


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321904 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed