DebugInfo: Make CGDebugInfo::getStaticDataMemberDeclaration's argument type match the semantics

Rather than having a cast immediately inside the function, push that
type requirement out to the callers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188492 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGDebugInfo.h b/lib/CodeGen/CGDebugInfo.h
index 72d956e..f17d47a 100644
--- a/lib/CodeGen/CGDebugInfo.h
+++ b/lib/CodeGen/CGDebugInfo.h
@@ -357,7 +357,7 @@
   /// getStaticDataMemberDeclaration - Return debug info descriptor to
   /// describe in-class static data member declaration for the given
   /// out-of-class definition.
-  llvm::DIDerivedType getStaticDataMemberDeclaration(const Decl *D);
+  llvm::DIDerivedType getStaticDataMemberDeclaration(const VarDecl *D);
 
   /// getFunctionName - Get function name for the given FunctionDecl. If the
   /// name is constructred on demand (e.g. C++ destructor) then the name