CodeGen: Remove more ilist iterator implicit conversions, NFC

llvm-svn: 249879
diff --git a/llvm/lib/CodeGen/InterferenceCache.cpp b/llvm/lib/CodeGen/InterferenceCache.cpp
index fd5749b..f8cc247 100644
--- a/llvm/lib/CodeGen/InterferenceCache.cpp
+++ b/llvm/lib/CodeGen/InterferenceCache.cpp
@@ -144,7 +144,8 @@
     PrevPos = Start;
   }
 
-  MachineFunction::const_iterator MFI = MF->getBlockNumbered(MBBNum);
+  MachineFunction::const_iterator MFI =
+      MF->getBlockNumbered(MBBNum)->getIterator();
   BlockInterference *BI = &Blocks[MBBNum];
   ArrayRef<SlotIndex> RegMaskSlots;
   ArrayRef<const uint32_t*> RegMaskBits;