USB: usbnet reports minidriver name through ethtool

Update "usbnet" so that ethtool reports the name of the minidriver in use
(e.g. asix, cdc_ether, dm9601, rndis_host) instead of "usbnet".  This is a
better match to how other network drivers work, resolving a minor open issue.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/net/usbnet.h b/drivers/usb/net/usbnet.h
index 07c70ab..cbb53e0 100644
--- a/drivers/usb/net/usbnet.h
+++ b/drivers/usb/net/usbnet.h
@@ -29,6 +29,7 @@
 	/* housekeeping */
 	struct usb_device	*udev;
 	struct driver_info	*driver_info;
+	const char		*driver_name;
 	wait_queue_head_t	*wait;
 	struct mutex		phy_mutex;