More arch header unification clean up.

Change-Id: If8bd2e754eac9c23dfedecae0afcd50ebb58010a
diff --git a/inc/hf/arch/cpu.h b/inc/hf/arch/cpu.h
index 24f00c0..aba76aa 100644
--- a/inc/hf/arch/cpu.h
+++ b/inc/hf/arch/cpu.h
@@ -20,6 +20,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "hf/arch/types.h"
+
 #include "hf/addr.h"
 
 /**