PPC: [turbofan] Add an InterpreterDispatch linkage type.

src/compiler/ppc/linkage-ppc.cc

Index: src/compiler/ppc/linkage-ppc.cc
diff --git a/src/compiler/ppc/linkage-ppc.cc b/src/compiler/ppc/linkage-ppc.cc
index 677e9d0e6c6c609bafdd89ed0d142afbd4898bf9..ebea4452aea62c7230ad263dff0e3de0dc89f50d 100644
--- a/src/compiler/ppc/linkage-ppc.cc
+++ b/src/compiler/ppc/linkage-ppc.cc
@@ -67,6 +67,12 @@ CallDescriptor* Linkage::GetSimplifiedCDescriptor(Zone* zone,
   return LH::GetSimplifiedCDescriptor(zone, sig);
 }
 
+
+CallDescriptor* Linkage::GetInterpreterDispatchDescriptor(
+    Zone* zone, const MachineSignature* sig) {
+  return LH::GetInterpreterDispatchDescriptor(zone, sig);
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8