Move #include of BitVector from .h to .cpp file.
Also remove unneeded #include and forward declaration.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177357 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SpillPlacement.cpp b/lib/CodeGen/SpillPlacement.cpp
index 320128a..c5bbba3 100644
--- a/lib/CodeGen/SpillPlacement.cpp
+++ b/lib/CodeGen/SpillPlacement.cpp
@@ -29,6 +29,7 @@
 
 #define DEBUG_TYPE "spillplacement"
 #include "SpillPlacement.h"
+#include "llvm/ADT/BitVector.h"
 #include "llvm/CodeGen/EdgeBundles.h"
 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"