tfmini_iic: fix bug

src/drivers/distance_sensor/tfmini_i2c/tfmini_i2c.cpp

@@ -137,13 +137,13 @@ TFMINI_I2C::init()
 		PX4_ERR("no sensors discovered");
 		return PX4_ERROR;
 	}
-
 	// If more than one sonar is detected, adjust the meaure interval to avoid sensor interference.
 	if (_sensor_count > 1) {
 		_measure_interval = TFMINI_I2C_INTERVAL_BETWEEN_SUCCESIVE_FIRES;
 	}
 
 	PX4_INFO("Total sensors connected: %i", _sensor_count);
+	start();
 	return PX4_OK;
 }