usb: musb: omap2430: turn off vbus on cable disconnect

On USB_EVENT_ID event the musb glue enables VBUS by calling
omap2430_musb_set_vbus(musb, 1) that sets the session bit, but on
USB_EVENT_NONE reverse action is never made, and that breaks PM.

Disable VBUS on USB_EVENT_NONE to be sure musb session is ended
on cable unplug so that PM works.
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/omap2430.c

@@ -291,6 +291,7 @@ static void omap_musb_set_mailbox(struct omap2430_glue *glue)
 
 		musb->xceiv->last_event = USB_EVENT_NONE;
 		if (musb->gadget_driver) {
+			omap2430_musb_set_vbus(musb, 0);
 			pm_runtime_mark_last_busy(dev);
 			pm_runtime_put_autosuspend(dev);
 		}