Rework wx_handler_pressure to get pressure not humidity from RTU slave

[SP8EBC]

`

        case WX_SOURCE_RTU:
	case WX_SOURCE_FULL_RTU: {

//		// get the value read from RTU registers
//		measurement_retval = rtu_get_humidity(&rte_wx_humidity, config_rtu);
//
//		// check
//		if (measurement_retval == MODBUS_RET_OK || measurement_retval == MODBUS_RET_DEGRADED) {
//
//			// set the flag that external temperature is available
//			output |= WX_HANDLER_PARAMETER_RESULT_HUMIDITY;
//
//			if (measurement_retval == BME280_OK) {
//				rte_wx_humidity_valid = rte_wx_humidity;
//			}
//		}
//

`