[llvm] Migrate llvm::make_unique to std::make_unique

Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

llvm-svn: 369013
diff --git a/llvm/lib/Target/AMDGPU/AMDGPULibFunc.cpp b/llvm/lib/Target/AMDGPU/AMDGPULibFunc.cpp
index a5bac25..ec2257f 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPULibFunc.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULibFunc.cpp
@@ -682,9 +682,9 @@
   }
 
   if (eatTerm(FuncName, "_Z"))
-    F.Impl = make_unique<AMDGPUMangledLibFunc>();
+    F.Impl = std::make_unique<AMDGPUMangledLibFunc>();
   else
-    F.Impl = make_unique<AMDGPUUnmangledLibFunc>();
+    F.Impl = std::make_unique<AMDGPUUnmangledLibFunc>();
   if (F.Impl->parseFuncName(FuncName))
     return true;