MIPS: Clean up VMState a little bit.

src/mips/macro-assembler-mips.cc

Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc
index 66cb7e4ae67a2bf3cc7e341c99ad35fc2331cfcf..220d9fe0c7d929e6231be5e316c0fd778a13e2a8 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -3925,8 +3925,9 @@ void MacroAssembler::CallApiFunctionAndReturn(ExternalReference function,
   if (FLAG_log_timer_events) {
     FrameScope frame(this, StackFrame::MANUAL);
     PushSafepointRegisters();
-    PrepareCallCFunction(0, a0);
-    CallCFunction(ExternalReference::log_enter_external_function(isolate()), 0);
+    PrepareCallCFunction(1, a0);
+    li(a0, Operand(ExternalReference::isolate_address(isolate())));
+    CallCFunction(ExternalReference::log_enter_external_function(isolate()), 1);
     PopSafepointRegisters();
   }
 
@@ -3945,8 +3946,9 @@ void MacroAssembler::CallApiFunctionAndReturn(ExternalReference function,
   if (FLAG_log_timer_events) {
     FrameScope frame(this, StackFrame::MANUAL);
     PushSafepointRegisters();
-    PrepareCallCFunction(0, a0);
-    CallCFunction(ExternalReference::log_leave_external_function(isolate()), 0);
+    PrepareCallCFunction(1, a0);
+    li(a0, Operand(ExternalReference::isolate_address(isolate())));
+    CallCFunction(ExternalReference::log_leave_external_function(isolate()), 1);
     PopSafepointRegisters();
   }