usb: cdns3: Fix not calling dev_xxx with a device

ep0.c also need to include dm.h so dev_xxx can access udevice fields.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Tested-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index 8f81d17..83dbb5a 100644
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -2399,8 +2399,7 @@
 	case USB_SPEED_SUPER:
 		break;
 	default:
-		dev_err(cdns->dev, "invalid speed parameter %d\n",
-			speed);
+		dev_err(priv_dev->dev, "invalid speed parameter %d\n", speed);
 	}
 
 	priv_dev->gadget.speed = speed;