usb: gadget: Add bcdDevice for the MTU3 USB Gadget Controller

Add an entry in usb_gadget_controller_number() for the MTU3
gadget controller. It is used to bind the USB Ethernet driver.

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/usb/gadget/gadget_chips.h b/drivers/usb/gadget/gadget_chips.h
index 587204c..0cdf47c 100644
--- a/drivers/usb/gadget/gadget_chips.h
+++ b/drivers/usb/gadget/gadget_chips.h
@@ -161,6 +161,12 @@
 #define gadget_is_max3420(g)        0
 #endif
 
+#ifdef CONFIG_USB_MTU3_GADGET
+#define gadget_is_mtu3(g)        (!strcmp("mtu3-gadget", (g)->name))
+#else
+#define gadget_is_mtu3(g)        0
+#endif
+
 /**
  * usb_gadget_controller_number - support bcdDevice id convention
  * @gadget: the controller being driven
@@ -224,5 +230,7 @@
 		return 0x24;
 	else if (gadget_is_max3420(gadget))
 		return 0x25;
+	else if (gadget_is_mtu3(gadget))
+		return 0x26;
 	return -ENOENT;
 }