CodeGen: Don't set 'PMBuilder.DisableSimplifyLibCalls'

The simplify-libcalls pass has been removed from LLVM.  Thus
'PMBuilder.DisableSimplifyLibCalls' does not exist anymore.
The disabling/enabling of library call simplifications is
done through the TargetLibraryInfo which is already wired
up in Clang.

llvm-svn: 184458

clang/lib/CodeGen/BackendUtil.cpp

@@ -221,7 +221,6 @@ void EmitAssemblyHelper::CreatePasses(TargetMachine *TM) {
   PMBuilder.OptLevel = OptLevel;
   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
 
-  PMBuilder.DisableSimplifyLibCalls = !CodeGenOpts.SimplifyLibCalls;
   PMBuilder.DisableUnitAtATime = !CodeGenOpts.UnitAtATime;
   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;