This patch check maximum possible duration of charging/discharging.

If whole charging duration exceed 'desc->charging_max_duration_ms', cm
stop charging to prevent overcharge/overheat. And if discharging duration
exceed, charger cable is attached, after full-batt, cm start charging to
maintain fully charged state for battery.
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>