AMDGPU: Use lld as the linker again

Summary:
Now that LLVM is emitting version 2 of the AMD code object, we can
start using lld again for linking instead of our custom tool.

Reviewers: arsenm, kzhuravl

Subscribers: rafael, cfe-commits

Differential Revision: http://reviews.llvm.org/D19952

llvm-svn: 268648
diff --git a/clang/lib/Driver/Tools.h b/clang/lib/Driver/Tools.h
index d25d91d..c9d5c22 100644
--- a/clang/lib/Driver/Tools.h
+++ b/clang/lib/Driver/Tools.h
@@ -242,7 +242,7 @@
 
 class LLVM_LIBRARY_VISIBILITY Linker : public GnuTool {
 public:
-  Linker(const ToolChain &TC) : GnuTool("amdgpu::Linker", "amdphdrs", TC) {}
+  Linker(const ToolChain &TC) : GnuTool("amdgpu::Linker", "ld.lld", TC) {}
   bool isLinkJob() const override { return true; }
   bool hasIntegratedCPP() const override { return false; }
   void ConstructJob(Compilation &C, const JobAction &JA,