USB: serial: hook up reset_resume callback

The callback is now hooked up for any USB to serial driver that wants
it.  We only register the callback if any of the usb-serial structures
want it, this keeps the USB core happy.

Thanks to Alan Stern for the ideas on how to do this.

Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index c9f6514..86c0b45 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -1,7 +1,7 @@
 /*
  * USB Serial Converter stuff
  *
- *	Copyright (C) 1999 - 2005
+ *	Copyright (C) 1999 - 2012
  *	    Greg Kroah-Hartman (greg@kroah.com)
  *
  *	This program is free software; you can redistribute it and/or modify
@@ -249,6 +249,7 @@
 
 	int (*suspend)(struct usb_serial *serial, pm_message_t message);
 	int (*resume)(struct usb_serial *serial);
+	int (*reset_resume)(struct usb_serial *serial);
 
 	/* serial function calls */
 	/* Called by console and by the tty layer */