iio: adc: axp20x_adc: Add missing sentinel to AXP717 ADC channel maps

The AXP717 ADC channel maps is missing a sentinel entry at the end. This
causes a KASAN warning.

Add the missing sentinel entry.

Fixes: 5ba0cb9 ("iio: adc: axp20x_adc: add support for AXP717 ADC")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Link: https://patch.msgid.link/20250607135627.2086850-1-wens@kernel.org
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: wens

drivers/iio/adc/axp20x_adc.c

@@ -187,6 +187,7 @@ static struct iio_map axp717_maps[] = {
 		.consumer_channel = "batt_chrg_i",
 		.adc_channel_label = "batt_chrg_i",
 	},
+	{ }
 };
 
 /*