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/goku_udc.c b/drivers/usb/gadget/goku_udc.c
index 7f87805..ab9c924 100644
--- a/drivers/usb/gadget/goku_udc.c
+++ b/drivers/usb/gadget/goku_udc.c
@@ -1796,6 +1796,7 @@
 	spin_lock_init(&dev->lock);
 	dev->pdev = pdev;
 	dev->gadget.ops = &goku_ops;
+	dev->gadget.max_speed = USB_SPEED_FULL;
 
 	/* the "gadget" abstracts/virtualizes the controller */
 	dev_set_name(&dev->gadget.dev, "gadget");