feat(mediatek): add APU init flow

The patch brings preparation steps before powering on APU
(AI processing unit)

Change-Id: Ica01e035153ec6f3af0de6ba2c66b17a064f8c89
diff --git a/plat/mediatek/drivers/apusys/rules.mk b/plat/mediatek/drivers/apusys/rules.mk
new file mode 100644
index 0000000..1aa67bc
--- /dev/null
+++ b/plat/mediatek/drivers/apusys/rules.mk
@@ -0,0 +1,19 @@
+#
+# Copyright (c) 2023, MediaTek Inc. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+LOCAL_DIR := $(call GET_LOCAL_DIR)
+
+MODULE := apusys
+
+LOCAL_SRCS-y:= ${LOCAL_DIR}/apusys.c
+
+PLAT_INCLUDES += -I${LOCAL_DIR} -I${LOCAL_DIR}/${MTK_SOC}
+
+$(eval $(call MAKE_MODULE,$(MODULE),$(LOCAL_SRCS-y),$(MTK_BL)))
+
+SUB_RULES-y := ${LOCAL_DIR}/${MTK_SOC}
+
+$(eval $(call INCLUDE_MAKEFILE,$(SUB_RULES-y)))