driver: fix unused variable warning

from r147218.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147278 91177308-0d34-0410-b5e6-96231b3b80d8

tools/driver/cc1as_main.cpp

@@ -214,7 +214,7 @@ bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
   Opts.RelaxAll = Args->hasArg(OPT_relax_all);
   Opts.NoExecStack =  Args->hasArg(OPT_no_exec_stack);
 
-  return true;
+  return Success;
 }
 
 static formatted_raw_ostream *GetOutputStream(AssemblerInvocation &Opts,