HAL_SMACCM: fixed build for new AnalogIn API

libraries/AP_HAL_SMACCM/AnalogIn.h

@@ -11,6 +11,9 @@ public:
     float read_latest();
     void set_pin(uint8_t p);
     float voltage_average();
+    void set_stop_pin(uint8_t p) {}
+    void set_settle_time(uint16_t settle_time_ms) {}
+
 private:
     float _v;
 };