charge current interface

Charge current experiment I am trying, cherry-pick in caution

 Author:    Gokhan Moral <gm@alumni.bilkent.edu.tr>
	modified:   drivers/power/Makefile
	new file:   drivers/power/charge_current.c
	new file:   drivers/power/charge_current.h
	new file:   drivers/power/sec_battery_u1.c