tty: remove TTY_SOFT_SAK part from __do_SAK()

Remove the TTY_SOFT_SAK part. It is never defined, so this is only
confusing.

It was actually never defined since its introduction in
0.99.14g.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118071911.12059-2-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/tty_io.c

@@ -3028,9 +3028,6 @@ static int this_tty(const void *t, struct file *file, unsigned fd)
  */
 void __do_SAK(struct tty_struct *tty)
 {
-#ifdef TTY_SOFT_SAK
-	tty_hangup(tty);
-#else
 	struct task_struct *g, *p;
 	struct pid *session;
 	int		i;
@@ -3074,7 +3071,6 @@ void __do_SAK(struct tty_struct *tty)
 	} while_each_thread(g, p);
 	read_unlock(&tasklist_lock);
 	put_pid(session);
-#endif
 }
 
 static void do_SAK_work(struct work_struct *work)