feat(mt8188): add apusys ao devapc setting

Apusys ao devapc is a set of control registers inside APU, and it
controls the access permission of APU ao domain.
Moreover, apusys ao devapc must be set after apusys power init, so
we need to place the drivers in TF-A instead of coreboot.

Change-Id: Ife849c32d4dd9dca15432d4b8a51753fde61b148
diff --git a/plat/mediatek/drivers/apusys/mt8188/apusys_devapc.h b/plat/mediatek/drivers/apusys/mt8188/apusys_devapc.h
new file mode 100644
index 0000000..345705c
--- /dev/null
+++ b/plat/mediatek/drivers/apusys/mt8188/apusys_devapc.h
@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2023, MediaTek Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef APUSYS_DEVAPC_H
+#define APUSYS_DEVAPC_H
+
+int apusys_devapc_ao_init(void);
+
+#endif /* APUSYS_DEVAPC_H */