power: supply: ab8500_charger: Restrict ADC retrieveal

The AB8505 only has two ADC channels: the voltage and current
provided from VBUS (USB). It does not support AC charging at all.
Make sure we don't try to retrieve the non-existing channels.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/ab8500_charger.c

@@ -3443,6 +3443,7 @@ static int ab8500_charger_probe(struct platform_device *pdev)
 	di->parent = dev_get_drvdata(pdev->dev.parent);
 
 	/* Get ADC channels */
+	if (!is_ab8505(di->parent)) {
 		di->adc_main_charger_v = devm_iio_channel_get(dev, "main_charger_v");
 		if (IS_ERR(di->adc_main_charger_v)) {
 			ret = dev_err_probe(dev, PTR_ERR(di->adc_main_charger_v),
@@ -3455,6 +3456,7 @@ static int ab8500_charger_probe(struct platform_device *pdev)
 					    "failed to get ADC main charger current\n");
 			return ret;
 		}
+	}
 	di->adc_vbus_v = devm_iio_channel_get(dev, "vbus_v");
 	if (IS_ERR(di->adc_vbus_v)) {
 		ret = dev_err_probe(dev, PTR_ERR(di->adc_vbus_v),