MIPS: Remove the obsolete OverwriteMode optimization.

src/mips64/lithium-codegen-mips64.cc

Index: src/mips64/lithium-codegen-mips64.cc
diff --git a/src/mips64/lithium-codegen-mips64.cc b/src/mips64/lithium-codegen-mips64.cc
index 2796f8e65d88f390312640c1543af4c83d736149..dd099689402ebee9efa05f1962c93ede0ca68219 100644
--- a/src/mips64/lithium-codegen-mips64.cc
+++ b/src/mips64/lithium-codegen-mips64.cc
@@ -1997,8 +1997,7 @@ void LCodeGen::DoArithmeticT(LArithmeticT* instr) {
   DCHECK(ToRegister(instr->right()).is(a0));
   DCHECK(ToRegister(instr->result()).is(v0));
 
-  Handle<Code> code =
-      CodeFactory::BinaryOpIC(isolate(), instr->op(), NO_OVERWRITE).code();
+  Handle<Code> code = CodeFactory::BinaryOpIC(isolate(), instr->op()).code();
   CallCode(code, RelocInfo::CODE_TARGET, instr);
   // Other arch use a nop here, to signal that there is no inlined
   // patchable code. Mips does not need the nop, since our marker