[PowerPC] Don't schedule VSX copy legalization unless VSX is enabled

There is no need to schedule this extra pass if it will have nothing to do.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204594 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/PowerPC/PPCTargetMachine.cpp

@@ -160,7 +160,8 @@ bool PPCPassConfig::addInstSelector() {
     addPass(createPPCCTRLoopsVerify());
 #endif
 
-  addPass(createPPCVSXCopyPass());
+  if (getPPCSubtarget().hasVSX())
+    addPass(createPPCVSXCopyPass());
 
   return false;
 }