iio: adc: axp288: remove redundant duplicate const on axp288_adc_channels

duplicate const can be removed, it is redundant. Found by static
analysis using smatch.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/axp288_adc.c

@@ -46,7 +46,7 @@ struct axp288_adc_info {
 	struct regmap *regmap;
 };
 
-static const struct iio_chan_spec const axp288_adc_channels[] = {
+static const struct iio_chan_spec axp288_adc_channels[] = {
 	{
 		.indexed = 1,
 		.type = IIO_TEMP,