iio: adc: mp2629: fix potential array out of bound access

Add sentinel at end of maps to avoid potential array out of
bound access in iio core.

Fixes: 7abd9fb ("iio: adc: mp2629: Add support for mp2629 ADC driver")
Signed-off-by: Saravanan Sekar <sravanhome@gmail.com>
Link: https://lore.kernel.org/r/20221029093000.45451-4-sravanhome@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: ssekar15

drivers/iio/adc/mp2629_adc.c

@@ -57,7 +57,8 @@ static struct iio_map mp2629_adc_maps[] = {
 	MP2629_MAP(SYSTEM_VOLT, "system-volt"),
 	MP2629_MAP(INPUT_VOLT, "input-volt"),
 	MP2629_MAP(BATT_CURRENT, "batt-current"),
-	MP2629_MAP(INPUT_CURRENT, "input-current")
+	MP2629_MAP(INPUT_CURRENT, "input-current"),
+	{ }
 };
 
 static int mp2629_read_raw(struct iio_dev *indio_dev,