px30 is a Quad-core soc and Cortex-a53 inside.
This patch supports the following functions:
1. basic platform setup
2. power up/off cpus
3. suspend/resume cpus
4. suspend/resume system
5. reset system
6. power off system

Change-Id: I73d55aa978096c078242be921abe0ddca9e8f67e
Signed-off-by: XiaoDong Huang <derrick.huang@rock-chips.com>