Remove PPCScoreboardHazardRecognizer

PPCScoreboardHazardRecognizer was a subclass of ScoreboardHazardRecognizer
which did only one thing: filtered out nodes in EmitInstruction for which
DAG->getInstrDesc(SU) returned NULL. This used to be the case for PPC pseudo
instructions. As far as I can tell, this is no longer true, and so we can use
ScoreboardHazardRecognizer directly.

llvm-svn: 196171
diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
index 87e13ef..bdeb649 100644
--- a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -61,7 +61,7 @@
   if (Directive == PPC::DIR_440 || Directive == PPC::DIR_A2 ||
       Directive == PPC::DIR_E500mc || Directive == PPC::DIR_E5500) {
     const InstrItineraryData *II = TM->getInstrItineraryData();
-    return new PPCScoreboardHazardRecognizer(II, DAG);
+    return new ScoreboardHazardRecognizer(II, DAG);
   }
 
   return TargetInstrInfo::CreateTargetHazardRecognizer(TM, DAG);
@@ -82,7 +82,7 @@
     return new PPCHazardRecognizer970(TM);
   }
 
-  return new PPCScoreboardHazardRecognizer(II, DAG);
+  return new ScoreboardHazardRecognizer(II, DAG);
 }
 
 // Detect 32 -> 64-bit extensions where we may reuse the low sub-register.