tty: Fallout from tty-move-canon-specials

Today's linux-next build (x86_64 allmodconfig) failed like this:

/drivers/char/tty_ioctl.c: In function 'change_termios':
drivers/isdn/capi/capi.c:1234: error: implicit declaration of function 'n_tty_ioctl'
drivers/isdn/gigaset/ser-gigaset.c: In function 'gigaset_tty_ioctl':
drivers/isdn/gigaset/ser-gigaset.c:648: error: implicit declaration of function 'n_tty_ioctl'

Introduced by commit 686b5e4aea05a80e370dc931b7f4a8d03c80da54
("tty-move-canon-specials").  I added the following patch (which may not
be correct).
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/isdn/capi/capi.c

@@ -1231,7 +1231,7 @@ static int capinc_tty_ioctl(struct tty_struct *tty, struct file * file,
 	int error = 0;
 	switch (cmd) {
 	default:
-		error = n_tty_ioctl (tty, file, cmd, arg);
+		error = n_tty_ioctl_helper(tty, file, cmd, arg);
 		break;
 	}
 	return error;

drivers/isdn/gigaset/ser-gigaset.c

@@ -645,7 +645,7 @@ gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,
 	case TCGETS:
 	case TCGETA:
 		/* pass through to underlying serial device */
-		rc = n_tty_ioctl(tty, file, cmd, arg);
+		rc = n_tty_ioctl_helper(tty, file, cmd, arg);
 		break;
 
 	case TCFLSH:
@@ -660,7 +660,7 @@ gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,
 			break;
 		}
 		/* flush the serial port's buffer */
-		rc = n_tty_ioctl(tty, file, cmd, arg);
+		rc = n_tty_ioctl_helper(tty, file, cmd, arg);
 		break;
 
 	case FIONREAD: