[clang] Make amdgpu-arch tool work on Windows

Currently amdgpu-arch tool detects AMD GPU by dynamically
loading HSA runtime shared library and using HSA API's,
which is not available on Windows.

This patch makes it work on Windows by dynamically loading
HIP runtime dll and using HIP API's.

Reviewed by: Matt Arsenault, Joseph Huber, Johannes Doerfert

Differential Revision: https://reviews.llvm.org/D153725