usbnet: Resubmit interrupt URB if device is open

Resubmit interrupt URB if device is open.  Use a flag set in
usbnet_open() to determine this state.  Also kill and free
interrupt URB in usbnet_disconnect().

[Rebased off git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git]

Signed-off-by: Paul Stewart <pstew@chromium.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 0e18550..605b0aa 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -68,6 +68,7 @@
 #		define EVENT_RX_PAUSED	5
 #		define EVENT_DEV_WAKING 6
 #		define EVENT_DEV_ASLEEP 7
+#		define EVENT_DEV_OPEN	8
 };
 
 static inline struct usb_driver *driver_of(struct usb_interface *intf)