[turbofan] Add an InterpreterDispatch linkage type.

src/compiler/x64/linkage-x64.cc

Index: src/compiler/x64/linkage-x64.cc
diff --git a/src/compiler/x64/linkage-x64.cc b/src/compiler/x64/linkage-x64.cc
index b272eb6f7668229a40b886bf292c3ad4320e0572..8bfbce02130c84bf44c01857084c1b50d94e052f 100644
--- a/src/compiler/x64/linkage-x64.cc
+++ b/src/compiler/x64/linkage-x64.cc
@@ -88,6 +88,12 @@ 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