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/gadget/dummy_hcd.c b/drivers/usb/gadget/dummy_hcd.c
index ab8f1b4..cf235d8 100644
--- a/drivers/usb/gadget/dummy_hcd.c
+++ b/drivers/usb/gadget/dummy_hcd.c
@@ -977,7 +977,7 @@
 
 	dum->gadget.name = gadget_name;
 	dum->gadget.ops = &dummy_ops;
-	dum->gadget.is_dualspeed = 1;
+	dum->gadget.max_speed = USB_SPEED_SUPER;
 
 	dev_set_name(&dum->gadget.dev, "gadget");
 	dum->gadget.dev.parent = &pdev->dev;