PPC: Updating kConstantPoolOffset to Match the variable defined in objects/code header file

Change-Id: I4ac61b2b1c9050b942028d07e78abf5fea1a9bbd
Reviewed-on: https://chromium-review.googlesource.com/c/1454837Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#59376}

src/ppc/macro-assembler-ppc.cc

@@ -911,7 +911,7 @@ void TurboAssembler::LoadConstantPoolPointerRegisterFromCodeTargetAddress(
     Register code_target_address) {
   lwz(kConstantPoolRegister,
       MemOperand(code_target_address,
-                 Code::kConstantPoolOffset - Code::kHeaderSize));
+                 Code::kConstantPoolOffsetOffset - Code::kHeaderSize));
   add(kConstantPoolRegister, kConstantPoolRegister, code_target_address);
 }