iio: adc: ti-ads1015: fix comparator polarity setting

The comparator polarity field in config register is not correctly
initialized as per the interrupt trigger setting.  Because the bitfield
definision is wrong and bit shifting is missed.

Fixes: d9f39babd8 ("iio: adc: ti-ads1015: add threshold event support")
Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ti-ads1015.c

@@ -52,7 +52,7 @@
 
 #define ADS1015_CFG_COMP_QUE_MASK	GENMASK(1, 0)
 #define ADS1015_CFG_COMP_LAT_MASK	BIT(2)
-#define ADS1015_CFG_COMP_POL_MASK	BIT(2)
+#define ADS1015_CFG_COMP_POL_MASK	BIT(3)
 #define ADS1015_CFG_COMP_MODE_MASK	BIT(4)
 #define ADS1015_CFG_DR_MASK	GENMASK(7, 5)
 #define ADS1015_CFG_MOD_MASK	BIT(8)
@@ -1017,10 +1017,12 @@ static int ads1015_probe(struct i2c_client *client,
 
 		switch (irq_trig) {
 		case IRQF_TRIGGER_LOW:
-			cfg_comp |= ADS1015_CFG_COMP_POL_LOW;
+			cfg_comp |= ADS1015_CFG_COMP_POL_LOW <<
+					ADS1015_CFG_COMP_POL_SHIFT;
 			break;
 		case IRQF_TRIGGER_HIGH:
-			cfg_comp |= ADS1015_CFG_COMP_POL_HIGH;
+			cfg_comp |= ADS1015_CFG_COMP_POL_HIGH <<
+					ADS1015_CFG_COMP_POL_SHIFT;
 			break;
 		default:
 			return -EINVAL;