SerialManager: set_console_baud uses first matching protocol

This ensures we set the baud to the first serial port with the specified
protocol instead of the last.

libraries/AP_SerialManager/AP_SerialManager.cpp

@@ -230,6 +230,7 @@ void AP_SerialManager::set_console_baud(enum SerialProtocol protocol) const
         if (state[i].protocol == protocol) {
             // set console's baud rate
             state[0].uart->begin(map_baudrate(state[i].baud));
+            return;
         }
     }
 }