feat(plat/mediatek/build_helpers): introduce mtk makefile

In order to modularize software libraries and platform drivers,
we create makefile helpers to treat a folder as a basic compile
unit.

Each module has a build rule (rules.mk) to describe driver and software
library source codes to be built in.

Signed-off-by: Leon Chen <leon.chen@mediatek.com>
Change-Id: Ib2113b259dc97937b7295b265509025b43b14077
diff --git a/plat/mediatek/build_helpers/options.mk b/plat/mediatek/build_helpers/options.mk
new file mode 100644
index 0000000..394a605
--- /dev/null
+++ b/plat/mediatek/build_helpers/options.mk
@@ -0,0 +1,17 @@
+#
+# Copyright (c) 2022, MediaTek Inc. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+# call add_defined_option to evaluate MTK defined value
+$(eval $(call add_defined_option,MTK_SIP_KERNEL_BOOT_ENABLE))
+$(eval $(call add_defined_option,PLAT_EXTRA_LD_SCRIPT))
+$(eval $(call add_defined_option,MTK_EXTRA_LINKERFILE))
+$(eval $(call add_defined_option,MTK_BL31_AS_BL2))
+$(eval $(call add_defined_option,MTK_BL33_IS_64BIT))
+$(eval $(call add_defined_option,PLAT_XLAT_TABLES_DYNAMIC))
+$(eval $(call add_defined_option,MTK_ADAPTED))
+$(eval $(call add_defined_option,MTK_SOC))
+$(eval $(call add_defined_option,UART_CLOCK))
+$(eval $(call add_defined_option,UART_BAUDRATE))