usbnet: add driver_priv pointer to 'struct usbnet'

Add a private data pointer to usbnet for rndis_wlan module to use.
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/usbnet.h

@@ -31,6 +31,7 @@ struct usbnet {
 	struct usb_interface	*intf;
 	struct driver_info	*driver_info;
 	const char		*driver_name;
+	void			*driver_priv;
 	wait_queue_head_t	*wait;
 	struct mutex		phy_mutex;
 	unsigned char		suspend_count;