usb: dwc3: gadget: use common is_selfpowered

Delete private selfpowered variable, and use common one.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index eccd29b..a03a485 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1415,7 +1415,7 @@
 	unsigned long		flags;
 
 	spin_lock_irqsave(&dwc->lock, flags);
-	dwc->is_selfpowered = !!is_selfpowered;
+	g->is_selfpowered = !!is_selfpowered;
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
 	return 0;