AP_SerialManager: add support for RichenPower generator

libraries/AP_SerialManager/AP_SerialManager.cpp

@@ -482,6 +482,9 @@ void AP_SerialManager::init()
                     state[i].uart->set_flow_control(AP_HAL::UARTDriver::FLOW_CONTROL_DISABLE);
                     break;
 
+                case SerialProtocol_Generator:
+                    break;
+
                 default:
                     state[i].uart->begin(map_baudrate(state[i].baud));
             }

libraries/AP_SerialManager/AP_SerialManager.h

@@ -137,6 +137,7 @@ public:
         SerialProtocol_RunCam = 26,
         SerialProtocol_Hott = 27,
         SerialProtocol_Scripting = 28,
+        SerialProtocol_Generator = 30,
     };
 
     // get singleton instance