* Simplify EINTR/ECANCEL error handling
1. Add semaphore uninterruptible wait function
2 .Replace semaphore wait loop with a single uninterruptible wait
3. Replace all sem_xxx to nxsem_xxx
* Unify the void cast usage
1. Remove void cast for function because many place ignore the returned value witout cast
2. Replace void cast for variable with UNUSED macro
wireless/bluetooth/bt_null.c:274:10: warning: implicit declaration of function 'bt_driver_register'; did you mean 'bt_netdev_register'? [-Wimplicit-function-declaration]
return bt_driver_register(&g_bt_null);
sim_bringup.c:324:9: error: too few arguments to function 'bt_netdev_register'
ret = bt_netdev_register();
found during testing.
drivers/wireless/bluetooth/bt_uart_shim.c: Change the task tname for
the HCI receiver task to bring it into line with the transmitter task.
