Clean up the codegen for invoking helper callout functions.

All invoked functions are documented in compiler/codegen/arm/CalloutHelper.h
Bug: 2567981

Change-Id: Ia7cd4107272df1b0b5588fbcc0aafcc6d0723d60
diff --git a/vm/compiler/codegen/arm/Codegen.h b/vm/compiler/codegen/arm/Codegen.h
index 8a340e5..da65bb5 100644
--- a/vm/compiler/codegen/arm/Codegen.h
+++ b/vm/compiler/codegen/arm/Codegen.h
@@ -23,6 +23,7 @@
  */
 
 #include "compiler/CompilerIR.h"
+#include "CalloutHelper.h"
 
 /*
  * loadConstant() sometimes needs to add a small imm to a pre-existing constant