[turbofan]: Elide extra move when accessing stack or frame register

src/mips64/frames-mips64.cc

Index: src/mips64/frames-mips64.cc
diff --git a/src/mips64/frames-mips64.cc b/src/mips64/frames-mips64.cc
index 2f0436184eed942c17facd45a89c8358b3a7d341..311b928a51fa19937543f41c5c0c073bc0b04e79 100644
--- a/src/mips64/frames-mips64.cc
+++ b/src/mips64/frames-mips64.cc
@@ -16,7 +16,8 @@ namespace v8 {
 namespace internal {
 
 
-Register JavaScriptFrame::fp_register() { return v8::internal::fp; }
+Register StandardFrame::sp_register() { return v8::internal::sp; }
+Register StandardFrame::fp_register() { return v8::internal::fp; }
 Register JavaScriptFrame::context_register() { return cp; }
 Register JavaScriptFrame::constant_pool_pointer_register() {
   UNREACHABLE();