USB: dwc3_otg: Add support for USB charging

Currently USB charging is not supported. Hence implement
charging API to notify PMIC to start/stop charging during
USB cable connect/disconnect respectively.

Also don't enable PHY interrupts for VBUS and ID if depends
on PMIC notifications.

Change-Id: Ie612101a3fc04b3d406f6a6ca2b928713f017b15
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>