Use uint32_t rather than int for memory modes.

Change-Id: I12b4d0cb0582d80bf86ca5dd99c7e462d776320f
diff --git a/inc/hf/cpu.h b/inc/hf/cpu.h
index 56f7982..7535454 100644
--- a/inc/hf/cpu.h
+++ b/inc/hf/cpu.h
@@ -67,7 +67,7 @@
 	ipaddr_t ipaddr;
 	vaddr_t vaddr;
 	vaddr_t pc;
-	int mode;
+	uint32_t mode;
 };
 
 struct vcpu {