Make TargetInstrInfo::isPredicable take a const reference, NFC

llvm-svn: 296901
diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
index 92fb226..6c148a3 100644
--- a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -1493,7 +1493,7 @@
   return Found;
 }
 
-bool PPCInstrInfo::isPredicable(MachineInstr &MI) const {
+bool PPCInstrInfo::isPredicable(const MachineInstr &MI) const {
   unsigned OpC = MI.getOpcode();
   switch (OpC) {
   default: