Replace a few more "fall through" comments with LLVM_FALLTHROUGH

Follow up to r278902. I had missed "fall through", with a space.

llvm-svn: 278970
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 0411a4a..3102a9a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1147,8 +1147,8 @@
     // See if the operation should be performed at a smaller bit width.
     if (TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl))
       return true;
+    LLVM_FALLTHROUGH;
   }
-  // FALL THROUGH
   default:
     // Just use computeKnownBits to compute output bits.
     TLO.DAG.computeKnownBits(Op, KnownZero, KnownOne, Depth);
@@ -2301,7 +2301,7 @@
       Ops.push_back(Op);
       return;
     }
-    // fall through
+    LLVM_FALLTHROUGH;
   case 'i':    // Simple Integer or Relocatable Constant
   case 'n':    // Simple Integer
   case 's': {  // Relocatable Constant