iio: addac: ad74413r: correct comparator gpio getters mask usage

The value of the GPIOs is currently altered using offsets rather
than masks. Make use of __assign_bit and the BIT macro to turn
the offsets into masks.

Fixes: fea251b6 ("iio: addac: add AD74413R driver")
Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220111074703.3677392-2-cosmin.tanislav@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/addac/ad74413r.c

@@ -134,7 +134,6 @@ struct ad74413r_state {
 #define AD74413R_CH_EN_MASK(x)		BIT(x)
 
 #define AD74413R_REG_DIN_COMP_OUT		0x25
-#define AD74413R_DIN_COMP_OUT_SHIFT_X(x)	x
 
 #define AD74413R_REG_ADC_RESULT_X(x)	(0x26 + (x))
 #define AD74413R_ADC_RESULT_MAX		GENMASK(15, 0)
@@ -316,7 +315,7 @@ static int ad74413r_gpio_get(struct gpio_chip *chip, unsigned int offset)
 	if (ret)
 		return ret;
 
-	status &= AD74413R_DIN_COMP_OUT_SHIFT_X(real_offset);
+	status &= BIT(real_offset);
 
 	return status ? 1 : 0;
 }
@@ -337,8 +336,7 @@ static int ad74413r_gpio_get_multiple(struct gpio_chip *chip,
 	for_each_set_bit_from(offset, mask, chip->ngpio) {
 		unsigned int real_offset = st->comp_gpio_offsets[offset];
 
-		if (val & BIT(real_offset))
-			*bits |= offset;
+		__assign_bit(offset, bits, val & BIT(real_offset));
 	}
 
 	return ret;