tty: Finish fixing up the init_dev interface to use ERR_PTR

Original suggestion and proposal from Sukadev Bhattiprolu.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index 4e6490b..c984500 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -501,11 +501,13 @@
 		return index;
 
 	mutex_lock(&tty_mutex);
-	retval = tty_init_dev(ptm_driver, index, &tty, 1);
+	tty = tty_init_dev(ptm_driver, index, 1);
 	mutex_unlock(&tty_mutex);
 
-	if (retval)
+	if (IS_ERR(tty)) {
+		retval = PTR_ERR(tty);
 		goto out;
+	}
 
 	set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
 	filp->private_data = tty;