The udc has three supplies: vdda (3.3V), vddi (1.2V) and vddosc (1.8-3.3V).
Turn these on and off on start and stop calls.
Signed-off-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Felipe Balbi <balbi@ti.com>