PPC/s390: [cleanup] combine 3 ResumeGenerator stubs into one

src/ppc/interface-descriptors-ppc.cc

Index: src/ppc/interface-descriptors-ppc.cc
diff --git a/src/ppc/interface-descriptors-ppc.cc b/src/ppc/interface-descriptors-ppc.cc
index feb81c4b2d3f93ab8e374b18a3359a43e6fd658c..82616493aef3e8fc921eee41cc20ef606d683d67 100644
--- a/src/ppc/interface-descriptors-ppc.cc
+++ b/src/ppc/interface-descriptors-ppc.cc
@@ -391,7 +391,8 @@ void ResumeGeneratorDescriptor::InitializePlatformSpecific(
   Register registers[] = {
       r3,  // the value to pass to the generator
       r4,  // the JSGeneratorObject to resume
-      r5   // the resume mode (tagged)
+      r5,  // the resume mode (tagged)
+      r6   // SuspendFlags (tagged)
   };
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }