[clang] Fix '-Woverloaded-virtual='. NFC

Author: darkbuck

clang/lib/CodeGen/CGOpenMPRuntimeGPU.h

@@ -163,12 +163,14 @@ class CGOpenMPRuntimeGPU : public CGOpenMPRuntime {
                           SourceLocation Loc) override;
 
   // Currently unsupported on the device.
+  using CGOpenMPRuntime::emitMessageClause;
   llvm::Value *emitMessageClause(CodeGenFunction &CGF, const Expr *Message,
                                  SourceLocation Loc) override;
 
   // Currently unsupported on the device.
-  virtual llvm::Value *emitSeverityClause(OpenMPSeverityClauseKind Severity,
-                                          SourceLocation Loc) override;
+  using CGOpenMPRuntime::emitSeverityClause;
+  llvm::Value *emitSeverityClause(OpenMPSeverityClauseKind Severity,
+                                  SourceLocation Loc) override;
 
   /// Emits call to void __kmpc_push_num_threads(ident_t *loc, kmp_int32
   /// global_tid, kmp_int32 num_threads) to generate code for 'num_threads'