Add domain suspend/resume support, Linux kernel
can "echo mem > /sys/power/state" to put system
into suspend mode, all CPUs and cluster will be
powered off and can be waked up if irq pending
in GIC, tested on i.MX8QM MEK board.

Since the power state has been implemented, switch
to use standard power state for CCI operations
instead of private cpu use count in i.MX8QM.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>