usb: gadget: replace usb_gadget::is_dualspeed with max_speed

This commit replaces usb_gadget's is_dualspeed field with
a max_speed field.

[ balbi@ti.com : Fixed DWC3 driver ]

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 25dbd86..5802720 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1986,7 +1986,7 @@
 	dev_set_name(&dwc->gadget.dev, "gadget");
 
 	dwc->gadget.ops			= &dwc3_gadget_ops;
-	dwc->gadget.is_dualspeed	= true;
+	dwc->gadget.max_speed		= USB_SPEED_SUPER;
 	dwc->gadget.speed		= USB_SPEED_UNKNOWN;
 	dwc->gadget.dev.parent		= dwc->dev;