PPC: Refine "Make whether or not a Code object should be created by masm explicit"

src/ppc/macro-assembler-ppc.h

Index: src/ppc/macro-assembler-ppc.h
diff --git a/src/ppc/macro-assembler-ppc.h b/src/ppc/macro-assembler-ppc.h
index befd5e280155264bc77836716b0dea5fed672138..adcb370dd5ec89d72347c8f26740883a696c4c25 100644
--- a/src/ppc/macro-assembler-ppc.h
+++ b/src/ppc/macro-assembler-ppc.h
@@ -110,10 +110,6 @@ bool AreAliased(Register reg1, Register reg2, Register reg3 = no_reg,
 // MacroAssembler implements a collection of frequently used macros.
 class MacroAssembler : public Assembler {
  public:
-  // The isolate parameter can be NULL if the macro assembler should
-  // not use isolate-dependent functionality. In this case, it's the
-  // responsibility of the caller to never invoke such function on the
-  // macro assembler.
   MacroAssembler(Isolate* isolate, void* buffer, int size,
                  CodeObjectRequired create_code_object);