Initialize platform for MediaTek mt8192

- Add basic platform setup
- Add mt8192 documentation at docs/plat/
- Add generic CPU helper functions
- Add basic register address

Change-Id: Ife34622105404a8227441aab939e3c55c96374e9
diff --git a/plat/mediatek/mt8192/include/plat_helpers.h b/plat/mediatek/mt8192/include/plat_helpers.h
new file mode 100644
index 0000000..9b550ee
--- /dev/null
+++ b/plat/mediatek/mt8192/include/plat_helpers.h
@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __PLAT_HELPERS_H__
+#define __PLAT_HELPERS_H__
+
+unsigned int plat_mediatek_calc_core_pos(u_register_t mpidr);
+
+#endif /* __PLAT_HELPERS_H__ */