Initialize platform for MediaTek MT8195

- Add basic platform setup
- Add MT8195 documentation at docs/plat/
- Add generic CPU helper functions
- Add basic register address

Change-Id: I7978e2f32e58900e5cf93f741ee8eaf8b8e3b842
Signed-off-by: Yidi Lin <yidi.lin@mediatek.com>
12 files changed