isdn: Remove ASYNC_CLOSING

The tty core no longer provides ASYNC_CLOSING. Use private flag for
same purpose, which is to disable AT-emulator output (why this is
necessary is not clear).

Cc: Karsten Keil <isdn@linux-pingi.de>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/isdn.h b/include/linux/isdn.h
index 1e9a0f2..df97c84 100644
--- a/include/linux/isdn.h
+++ b/include/linux/isdn.h
@@ -319,6 +319,7 @@
   int                   online;          /* 1 = B-Channel is up, drop data */
 					 /* 2 = B-Channel is up, deliver d.*/
   int                   dialing;         /* Dial in progress or ATA        */
+  int                   closing;
   int                   rcvsched;        /* Receive needs schedule         */
   int                   isdn_driver;	 /* Index to isdn-driver           */
   int                   isdn_channel;    /* Index to isdn-channel          */