Tidy up #includes, deleting a bunch of unnecessary #includes.

llvm-svn: 61715
diff --git a/llvm/lib/Target/ARM/ARMConstantPoolValue.h b/llvm/lib/Target/ARM/ARMConstantPoolValue.h
index 7b10565..d2b9066 100644
--- a/llvm/lib/Target/ARM/ARMConstantPoolValue.h
+++ b/llvm/lib/Target/ARM/ARMConstantPoolValue.h
@@ -15,7 +15,7 @@
 #define LLVM_TARGET_ARM_CONSTANTPOOLVALUE_H
 
 #include "llvm/CodeGen/MachineConstantPool.h"
-#include <ostream>
+#include <iosfwd>
 
 namespace llvm {