iio: adc: sc27xx: Fine tune the scale calibration values

Small adjustment the scale calibration value for the sc2731,
use new name sc2731_[big|small]_scale_graph_calib, and remove
the origin [big|small]_scale_graph_calib struct for unused.

Fixes: 8ba0dbfd (iio: adc: sc27xx: Add ADC scale calibration)
Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
Link: https://lore.kernel.org/r/20220419142458.884933-4-gengcixi@gmail.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>