feat(mt8188): enable apusys mailbox mpu protect

Enable apusys mailbox mpu protect.

Change-Id: Idbf67084037b7ecf4926f57a901075f98540ee57
diff --git a/plat/mediatek/drivers/apusys/apusys.c b/plat/mediatek/drivers/apusys/apusys.c
index 948bd9a..33cfe93 100644
--- a/plat/mediatek/drivers/apusys/apusys.c
+++ b/plat/mediatek/drivers/apusys/apusys.c
@@ -11,6 +11,7 @@
 #include "apusys.h"
 #include "apusys_devapc.h"
 #include "apusys_power.h"
+#include "apusys_rv.h"
 #include "apusys_security_ctrl_plat.h"
 #include <lib/mtk_init/mtk_init.h>
 #include <mtk_sip_svc.h>
@@ -54,6 +55,7 @@
 	}
 
 	apusys_security_ctrl_init();
+	apusys_rv_mbox_mpu_init();
 
 	return 0;
 }