AMDGPU: Use AMDGPU toolchain for other OSes

This would need more work to actually support them, but this is less
wrong than the default.

llvm-svn: 363390
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index e28ff55..17552b2 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -4617,6 +4617,8 @@
       TC = llvm::make_unique<toolchains::Solaris>(*this, Target, Args);
       break;
     case llvm::Triple::AMDHSA:
+    case llvm::Triple::AMDPAL:
+    case llvm::Triple::Mesa3D:
       TC = llvm::make_unique<toolchains::AMDGPUToolChain>(*this, Target, Args);
       break;
     case llvm::Triple::Win32: