Correct the PPC A2 misprediction penalty

The manual states that there is a minimum of 13 cycles from when the
mispredicted branch is issued to when the correct branch target is
issued.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178925 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/PowerPC/PPCScheduleA2.td

@@ -759,7 +759,7 @@ def PPCA2Model : SchedMachineModel {
   let LoadLatency = 6; // Optimistic load latency assuming bypass.
                        // This is overriden by OperandCycles if the
                        // Itineraries are queried instead.
-  let MispredictPenalty = 6;
+  let MispredictPenalty = 13;
 
   let Itineraries = PPCA2Itineraries;
 }