[PHIElimination] Use the same name for DEBUG_TYPE and pass name.

In an attempt to reduce the confusion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302742 91177308-0d34-0410-b5e6-96231b3b80d8

Author: dcci

lib/CodeGen/PHIElimination.cpp

@@ -34,7 +34,7 @@
 #include <algorithm>
 using namespace llvm;
 
-#define DEBUG_TYPE "phielim"
+#define DEBUG_TYPE "phi-node-elimination"
 
 static cl::opt<bool>
 DisableEdgeSplitting("disable-phi-elim-edge-splitting", cl::init(false),