tty: some ICANON magic is in the wrong places

Move the set up on ldisc change into the ldisc
Move the INQ/OUTQ cases into the driver not in shared ioctl code where it
gives bogus answers for other ldisc values

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/n_hdlc.c

@@ -764,7 +764,7 @@ static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
 		break;
 
 	default:
-		error = n_tty_ioctl (tty, file, cmd, arg);
+		error = n_tty_ioctl_helper(tty, file, cmd, arg);
 		break;
 	}
 	return error;