[Bluetooth] Fix unintentional fall-through in HCI line discipline

A trivial fix to (what looks like) an unintentional fall-through in the
HCI line discipline.
Signed-off-by: NOhad Ben-Cohen <ohad@bencohen.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/hci_ldisc.c

@@ -475,6 +475,7 @@ static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file * file,
 			tty->low_latency = 1;
 		} else
 			return -EBUSY;
+		break;
 
 	case HCIUARTGETPROTO:
 		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))