S390: Fix '[ic] Use the CallFunction builtin to invoke accessors.'

Fix native compilation error due to gcc error "call of overloaded
‘Operand(int)’ is ambiguous"

R=joransiu@ca.ibm.com, mbrandy@us.ibm.com, michael_dawson@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1847303004

Cr-Commit-Position: refs/heads/master@{#35218}

src/ic/s390/handler-compiler-s390.cc

@@ -43,7 +43,7 @@ void NamedLoadHandlerCompiler::GenerateLoadViaGetter(
       }
       __ Push(receiver);
       __ LoadAccessor(r3, holder, accessor_index, ACCESSOR_GETTER);
-      __ LoadImmP(r2, Operand(0));
+      __ LoadImmP(r2, Operand::Zero());
       __ Call(masm->isolate()->builtins()->CallFunction(
                   ConvertReceiverMode::kNotNullOrUndefined),
               RelocInfo::CODE_TARGET);