usb: dwc3-msm: support external vbus power_supply

External clients may provide VBUS power even when USB is not in use.
Support this by querying for an "ext-vbus" power_supply for which the
"usb" power_supply will act as a supplicant. When the external
power_supply sets its present and online states, the USB supply will
in turn notify the battery of the external power source.

Change-Id: I566ae4c4b047dcca2eb2d0f9aea56d19b53a9268
Signed-off-by: Jack Pham <jackp@codeaurora.org>
1 file changed