GitLab

1. Add SiP calls for subsystem power on/off and check support
2. Add subsystem power control related initialization in
   bl31_plat_setup.c
3. Add subsystem power on/off and power ack waiting functions
4. Update PCM code for subsystem physical power control logic

Change-Id: Ia0ebb1964c8f9758159bcf17c1813d76ef52cf64
Signed-off-by: yt.lee <yt.lee@mediatek.com>