Trim unnecessary #includes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53471 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMConstantPoolValue.h b/lib/Target/ARM/ARMConstantPoolValue.h
index db4c057..6361663 100644
--- a/lib/Target/ARM/ARMConstantPoolValue.h
+++ b/lib/Target/ARM/ARMConstantPoolValue.h
@@ -18,6 +18,8 @@
 
 namespace llvm {
 
+class GlobalValue;
+
 namespace ARMCP {
   enum ARMCPKind {
     CPValue,