usbnet: Use wwan%d interface name for mobile broadband devices

Add support for usbnet based devices like CDC-Ether to indicate that they
are actually mobile broadband devices. In that case use wwan%d as default
interface name.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index f814730..86c31b7 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -90,6 +90,7 @@
 #define FLAG_WLAN	0x0080		/* use "wlan%d" names */
 #define FLAG_AVOID_UNLINK_URBS 0x0100	/* don't unlink urbs at usbnet_stop() */
 #define FLAG_SEND_ZLP	0x0200		/* hw requires ZLPs are sent */
+#define FLAG_WWAN	0x0400		/* use "wwan%d" names */
 
 
 	/* init device ... can sleep, or cause probe() failure */