iio:adc:ad7476: Use GENMASK() macro

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/ad7476.c

@@ -14,6 +14,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/err.h>
 #include <linux/module.h>
+#include <linux/bitops.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -21,8 +22,6 @@
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
 
-#define RES_MASK(bits)	((1 << (bits)) - 1)
-
 struct ad7476_state;
 
 struct ad7476_chip_info {
@@ -117,7 +116,7 @@ static int ad7476_read_raw(struct iio_dev *indio_dev,
 		if (ret < 0)
 			return ret;
 		*val = (ret >> st->chip_info->channel[0].scan_type.shift) &
-			RES_MASK(st->chip_info->channel[0].scan_type.realbits);
+			GENMASK(st->chip_info->channel[0].scan_type.realbits - 1, 0);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		if (!st->chip_info->int_vref_uv) {