* add mac layer counter
* add more counters and Doxygen for MAC counters
* have a seperate counter for acked data transmission and refine the code based on the comments
* refine counters for acked and unacked transmissions
* fix check test error
* refine code style and use VerifyOrExit to exit
* move all events tracker to tx/rx done task, and add more counters
* fix other error counter
* refine counters structure to be clearer
* add Doxygen for the added thread errors
* fix conflicts
Some radio chips have memory-mapped regions for transmit and receive buffers.
This change allows the radio driver to pass those buffers, when available,
directly to upper layers and avoid unnecessary copies.
* Add an LQI field to the radio packet structure.
* Add an LQI field to the ThreadMessageInfo.
* Add an LQI field to the scan result.
* Print LQI value in CLI scan result.
This was originally here because of some misconfigured TTY settings,
and can cause problems when running on embedded devices.
Since the misconfigured TTY settings have been addressed, this check
is no longer needed.
* posix: logging: Use `stderr` instead of `stdout` for debug logging.
* posix: serial: Restore socket `termios` settings for `stdin` and `stdout` at exit.
Lu Wang