Use fixed regulator to control the voltage of vbus. Enable vbus
supply when usb start and disable vbus supply when usb stop.
Signed-off-by: NMeng Dongyang <daniel.meng@rock-chips.com>
Reviewed-by: NPhilipp Tomsich <philipp.tomsich@theobroma-systems.com>
Acked-by: NPhilipp Tomsich <philipp.tomsich@theobroma-systems.com>