tty: Remove TTY_HUPPING

Now that tty_ldisc_hangup() does not drop the tty lock, it is no
longer possible to observe TTY_HUPPING while holding the tty lock
on another cpu.

Remove TTY_HUPPING bit definition.

Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 28858eb..49001fa 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -544,8 +544,7 @@
 
 	old_ldisc = tty->ldisc;
 
-	if (test_bit(TTY_HUPPING, &tty->flags) ||
-	    test_bit(TTY_HUPPED, &tty->flags)) {
+	if (test_bit(TTY_HUPPED, &tty->flags)) {
 		/* We were raced by the hangup method. It will have stomped
 		   the ldisc data and closed the ldisc down */
 		tty_ldisc_enable_pair(tty, o_tty);