LOG_DBG print messages twice, but other log macros are correct.

[ACuteCoder]

My code:

```

  LOG_DBG("button_pressed");

  LOG_INF("button_pressed");

  LOG_WRN("button_pressed");

  LOG_ERR("button_pressed");

```

The output of RTT:

```

[00:00:24.574,157] <dbg> blinky: button_pressed: button_pressed
[00:00:24.574,188] <inf> blinky: button_pressed
[00:00:24.574,188] <wrn> blinky: button_pressed
[00:00:24.574,188] <err> blinky: button_pressed

```

[Turbo J]

Intended behaviour, see CONFIG_LOG_FUNC_NAME_PREFIX_DBG in documentation. Its enabled by default and causes the function name to be printed out in LOG_DBG statements.