arm/ls102xa: Add PSCI support for ls102xa

Base on PSCI services, implement CPU_ON/CPU_OFF for ls102xa platform.

Tested on LS1021AQDS, LS1021ATWR.
Test CPU hotplug times: 60K
Test kernel boot times: 1.2K

Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>
Acked-by: Alison Wang <alison.wang@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
4 files changed