tty: Remove tty_unhangup() declaration

The tty_unhangup() function is not defined.
Reviewed-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/tty.h

@@ -435,7 +435,6 @@ extern int is_ignored(int sig);
 extern int tty_signal(int sig, struct tty_struct *tty);
 extern void tty_hangup(struct tty_struct *tty);
 extern void tty_vhangup(struct tty_struct *tty);
-extern void tty_unhangup(struct file *filp);
 extern int tty_hung_up_p(struct file *filp);
 extern void do_SAK(struct tty_struct *tty);
 extern void __do_SAK(struct tty_struct *tty);