iio: adc: max1027: Fix the number of max1X31 channels

iio: adc: max1027: Fix the number of max1X31 channels

The macro MAX1X29_CHANNELS() already calls MAX1X27_CHANNELS().
Calling MAX1X27_CHANNELS() before MAX1X29_CHANNELS() in the definition
of MAX1X31_CHANNELS() declares the first 8 channels twice. So drop this
extra call from the MAX1X31 channels list definition.

Fixes: 31d7fdf0688a ("iio: adc: max1027: Prepare the introduction of different resolutions")
Cc: stable@vger.kernel.org
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20210818111139.330636-3-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>