hackrf: add support for transmitter

Hello Antti Palosaari,

The patch 8bc4a9ed8504: "[media] hackrf: add support for transmitter" from Oct 10, 2015, leads to the following static checker warning:

drivers/media/usb/hackrf/hackrf.c:1533 hackrf_probe()
error: we previously assumed 'dev' could be null (see line 1366)

drivers/media/usb/hackrf/hackrf.c
1520 dev_notice(dev->dev, "SDR API is still slightly experimental and functionality changes may follow\n");
1521 return 0;
1522 err_video_unregister_device_rx:
1523 video_unregister_device(&dev->rx_vdev);
1524 err_v4l2_device_unregister:
1525 v4l2_device_unregister(&dev->v4l2_dev);
1526 err_v4l2_ctrl_handler_free_tx:
1527 v4l2_ctrl_handler_free(&dev->tx_ctrl_handler);
1528 err_v4l2_ctrl_handler_free_rx:
1529 v4l2_ctrl_handler_free(&dev->rx_ctrl_handler);
1530 err_kfree:
1531 kfree(dev);
1532 err:

  1533          dev_dbg(dev->dev, "failed=%d\n", ret);
                        ^^^

"dev" is either freed or NULL. Also this change is basically unrelated to adding transmitter support... :/

1534 return ret;
1535 }

regards,
dan carpenter