Working - except when exiting from bootloader

Fixes the `Waiting for Data` problem in configurator when:

- Clicking on `Save and Reboot` button
- Clicking on `Flash Firmware`  button

When the system reboots after programming the new firmware it still
needs a connect/disconnect cycle to work normal. This cannot be solved
since the bootloader is a fixed program in ROM.

Fix is for F1 targets and only tested on naze boards.

src/main/io/serial_msp.c

@@ -1823,10 +1823,7 @@ void mspProcess(void)
         }
 
         if (isRebootScheduled) {
-            // pause a little while to allow response to be sent
-            while (!isSerialTransmitBufferEmpty(candidatePort->port)) {
-                delay(50);
-            }
+            waitForSerialPortToFinishTransmitting(candidatePort->port);
             stopMotors();
             handleOneshotFeatureChangeOnRestart();
             systemReset();