DebugInfo: Use new LLVM API for DebugLoc

Use the new API for `DebugLoc` added in r233573 before the old one
disappears.

llvm-svn: 233589
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index ae511ae..9abc885 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -2350,7 +2350,7 @@
       callSite->replaceAllUsesWith(newCall.getInstruction());
 
     // Copy debug location attached to CI.
-    if (!callSite->getDebugLoc().isUnknown())
+    if (callSite->getDebugLoc())
       newCall->setDebugLoc(callSite->getDebugLoc());
     callSite->eraseFromParent();
   }