[Atomics] Remove Atomics code stubs; use TF ops

src/mips64/code-stubs-mips64.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_MIPS64
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 5737 matching lines @@
       ExternalReference::invoke_accessor_getter_callback(isolate());
 
   // +3 is to skip prolog, return address and name handle.
   MemOperand return_value_operand(
       fp, (PropertyCallbackArguments::kReturnValueOffset + 3) * kPointerSize);
   CallApiFunctionAndReturn(masm, api_function_address, thunk_ref,
                            kStackUnwindSpace, kInvalidStackOffset,
                            return_value_operand, NULL);
 }
 
-void AtomicsLoadStub::Generate(MacroAssembler* masm) {
-  // TODO(binji)
-}
-
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS64