usb: dwc3-generic: support external vbus regulator

Add support for a vbus-supply regulator specified in devicetree. This
provides generic support to avoid hardcoded GPIO configuration in board
init code.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
1 file changed