PEI: rename PEI.h to PrologEpilogInserter.h to adhere to file naming standard

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71678 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ShrinkWrapping.cpp b/lib/CodeGen/ShrinkWrapping.cpp
index 7a1b4ea..e44a138 100644
--- a/lib/CodeGen/ShrinkWrapping.cpp
+++ b/lib/CodeGen/ShrinkWrapping.cpp
@@ -34,7 +34,7 @@
 
 #define DEBUG_TYPE "shrink-wrap"
 
-#include "PEI.h"
+#include "PrologEpilogInserter.h"
 #include "llvm/CodeGen/MachineDominators.h"
 #include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/CodeGen/MachineInstr.h"