[cleanup] Drop unused scratch register from {load,store}_calling_convention

src/ic/s390/access-compiler-s390.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_S390
 
 #include "src/ic/access-compiler.h"
 
 namespace v8 {
 namespace internal {
 
 #define __ ACCESS_MASM(masm)
 
 void PropertyAccessCompiler::GenerateTailCall(MacroAssembler* masm,
                                               Handle<Code> code) {
   __ Jump(code, RelocInfo::CODE_TARGET);
 }
 
 Register* PropertyAccessCompiler::load_calling_convention() {
-  // receiver, name, scratch1, scratch2, scratch3, scratch4.
+  // receiver, name, scratch1, scratch2, scratch3.
   Register receiver = LoadDescriptor::ReceiverRegister();
   Register name = LoadDescriptor::NameRegister();
-  static Register registers[] = {receiver, name, r5, r2, r6, r7};
+  static Register registers[] = {receiver, name, r5, r2, r6};
   return registers;
 }
 
 Register* PropertyAccessCompiler::store_calling_convention() {
-  // receiver, name, scratch1, scratch2, scratch3.
+  // receiver, name, scratch1, scratch2.
   Register receiver = StoreDescriptor::ReceiverRegister();
   Register name = StoreDescriptor::NameRegister();
-  static Register registers[] = {receiver, name, r5, r6, r7};
+  static Register registers[] = {receiver, name, r5, r6};
   return registers;
 }
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_S390