iio: adc: qcom-spmi-adc5: Verify channel numbers from DT

The driver only defines a subset of all possible ADC channels. Channel
numbers read from the device tree are accepted as long as they don't
exceed a max value, even when no channel definition exists. Add a
check to abort initialization in this case.
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/qcom-spmi-adc5.c

@@ -519,7 +519,8 @@ static int adc5_get_dt_channel_data(struct adc5_chip *adc,
 		return ret;
 	}
 
-	if (chan > ADC5_PARALLEL_ISENSE_VBAT_IDATA) {
+	if (chan > ADC5_PARALLEL_ISENSE_VBAT_IDATA ||
+	    !data->adc_chans[chan].datasheet_name) {
 		dev_err(dev, "%s invalid channel number %d\n", name, chan);
 		return -EINVAL;
 	}