InstrProf: Fix MSVC after r205023

llvm-svn: 205025
diff --git a/clang/lib/CodeGen/CodeGenPGO.cpp b/clang/lib/CodeGen/CodeGenPGO.cpp
index ef490ff..81af8cd 100644
--- a/clang/lib/CodeGen/CodeGenPGO.cpp
+++ b/clang/lib/CodeGen/CodeGenPGO.cpp
@@ -815,8 +815,8 @@
 }
 
 static void emitRuntimeHook(CodeGenModule &CGM) {
-  constexpr const char *RuntimeVarName = "__llvm_profile_runtime";
-  constexpr const char *RuntimeUserName = "__llvm_profile_runtime_user";
+  const char *RuntimeVarName = "__llvm_profile_runtime";
+  const char *RuntimeUserName = "__llvm_profile_runtime_user";
   if (CGM.getModule().getGlobalVariable(RuntimeVarName))
     return;