iio: adc: stm32-dfsdm: Avoid dereferencing ->currentmode

This is an internal variable of the core, let's use the
iio_buffer_enabled() helper which is exported for the following purpose:
telling if the current mode is a buffered mode, which is precisely what
this driver looks for.

Cc: Olivier Moysan <olivier.moysan@foss.st.com>
Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20220207143840.707510-4-miquel.raynal@bootlin.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/stm32-dfsdm-adc.c

@@ -466,8 +466,7 @@ static int stm32_dfsdm_channels_configure(struct iio_dev *indio_dev,
 	 * In continuous mode, use fast mode configuration,
 	 * if it provides a better resolution.
 	 */
-	if (adc->nconv == 1 && !trig &&
-	    (indio_dev->currentmode & INDIO_BUFFER_SOFTWARE)) {
+	if (adc->nconv == 1 && !trig && iio_buffer_enabled(indio_dev)) {
 		if (fl->flo[1].res >= fl->flo[0].res) {
 			fl->fast = 1;
 			flo = &fl->flo[1];
@@ -562,7 +561,7 @@ static int stm32_dfsdm_filter_configure(struct iio_dev *indio_dev,
 		cr1 = DFSDM_CR1_RCH(chan->channel);
 
 		/* Continuous conversions triggered by SPI clk in buffer mode */
-		if (indio_dev->currentmode & INDIO_BUFFER_SOFTWARE)
+		if (iio_buffer_enabled(indio_dev))
 			cr1 |= DFSDM_CR1_RCONT(1);
 
 		cr1 |= DFSDM_CR1_RSYNC(fl->sync_mode);