iio: adc: ad7266: don't set masklength

The masklength field is marked as [INTERN] and should not be set by
drivers, so remove the assignment in the ad7266 driver.

__iio_device_register() will populate this field with the correct value.

Signed-off-by: David Lechner <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/adc/ad7266.c

···
 	indio_dev->channels = chan_info->channels;
 	indio_dev->num_channels = chan_info->num_channels;
 	indio_dev->available_scan_masks = chan_info->scan_masks;
-	indio_dev->masklength = chan_info->num_channels - 1;
 }
 
 static const char * const ad7266_gpio_labels[] = {