SM6FBQ / HackRF clone - History

Fix USB requests that were responding with data from the stack.

Merge hackrf_stop_tx_cmd and hackrf_start_tx_cmd.

These both do the same thing: set transceiver mode to OFF.

Remove delays from hackrf_stop_rx_cmd and hackrf_stop_tx_cmd.

These were added in #805, as a workaround to prevent their parent
functions from returning before transfer cancellations had completed.
This has since been fixed properly in #1029.

Remove request_exit() function.

This just set the do_exit flag, and was now only called in one place.

Set streaming flag in prepare_transfers().

This simplifies prepare_setup_transfers(), which was just setting
the flag if prepare_transfers() returned success, and passing on
its return value.

Set streaming flag in prepare_setup_transfers().

Avoids conditionally duplicating this across three other places.

Clear streaming flag in cancel_transfers().

Moving this into cancel_transfers() avoids duplicating it in the two
stop functions.

Simplify hackrf_libusb_transfer_callback.

There are now only two possible outcomes to this function: either we
successfully resubmitted a transfer, or the transfer is finished and we
end up calling transfer_finished().

So we can go ahead and simplify it accordingly.