ENGR00215718: battery: fix issure that coulomb data increases in discharger

ENGR00215718: battery: fix issure that coulomb data increases in discharger

Hardware cannot support battery internal resistance and coulomb calculation,
estimate data only by battery voltage.The true battery voltage will change to
a bit lower about 50mV~500mV than normal voltage with playing game or video or
other consumption actions, then change back to normal voltage with finishing
playing game or video or other consumption actions in the discharger stage.

Signed-off-by: Rong Dian <b38775@freescale.com>