usbnet: Set link down initially for drivers that update link state

Some usbnet drivers update link state while others do not due to
hardware limitations.  Add a flag to distinguish those that do, and
set the link down initially for their devices.

This is intended to fix this bug: http://bugs.debian.org/444043

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/dm9601.c b/drivers/net/usb/dm9601.c
index a2b30a1..3d406f9 100644
--- a/drivers/net/usb/dm9601.c
+++ b/drivers/net/usb/dm9601.c
@@ -611,7 +611,7 @@
 
 static const struct driver_info dm9601_info = {
 	.description	= "Davicom DM9601 USB Ethernet",
-	.flags		= FLAG_ETHER,
+	.flags		= FLAG_ETHER | FLAG_LINK_INTR,
 	.bind		= dm9601_bind,
 	.rx_fixup	= dm9601_rx_fixup,
 	.tx_fixup	= dm9601_tx_fixup,