tty: Remove ASYNC_CLOSING

The tty core no longer provides nor uses ASYNC_CLOSING; remove from
tty_port_close_start() and tty_port_close_end() as well as tty drivers
which open-code these state changes. Unfortunately, even though the
bit is masked from userspace, its inclusion in a uapi header precludes
removing the macro.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: linux-cris-kernel@axis.com
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/crisv10.c

@@ -3610,7 +3610,6 @@ rs_close(struct tty_struct *tty, struct file * filp)
 		local_irq_restore(flags);
 		return;
 	}
-	info->port.flags |= ASYNC_CLOSING;
 	/*
 	 * Now we wait for the transmit buffer to clear; and we notify
 	 * the line discipline to only process XON/XOFF characters.
@@ -3649,7 +3648,7 @@ rs_close(struct tty_struct *tty, struct file * filp)
 			schedule_timeout_interruptible(info->port.close_delay);
 		wake_up_interruptible(&info->port.open_wait);
 	}
-	info->port.flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING);
+	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
 	local_irq_restore(flags);
 
 	/* port closed */