Dont cast away const needlessly. Found by gcc48 -Wcast-qual.

llvm-svn: 163325
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index d6c39c6..d1ccfe6 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -157,7 +157,7 @@
       OS << OID->getName();
   } else if (const ObjCCategoryImplDecl *OCD = 
              dyn_cast<const ObjCCategoryImplDecl>(DC)){
-      OS << ((NamedDecl *)OCD)->getIdentifier()->getNameStart() << '(' <<
+      OS << ((const NamedDecl *)OCD)->getIdentifier()->getNameStart() << '(' <<
           OCD->getIdentifier()->getNameStart() << ')';
   }
   OS << ' ' << OMD->getSelector().getAsString() << ']';