On Spreadtrum platform, we need power off system through external SC27xx
series PMICs including the SC2720, SC2721, SC2723, SC2730 and SC2731 chips.
Thus this patch adds SC27xx series PMICs power-off support.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>