ENGR00231808: Add epdc pmic shut down feature

ENGR00231808: Add epdc pmic shut down feature

For some cases, system maybe restart with epdc pmic on.
If epdc pmic on for sometime(2~3s), the current epdc pmic consume will increase
obviously, then the total current of board maybe exceed to the current limit,
which will pull down the input voltage to lead to the system pmic reset,
an un-expected POR reset occurs.
So it is necessary to close epdc pmic before system restart.

This patch is added by Robby Cai<r63905@freescale.com>

Signed-off-by: LiGang <b41990@freescale.com>
(cherry picked from commit ee9ffb4307b2b3d7440fc3468b0faaace3d2829e)