iio: humidity: hts221: move register definitions to sensor structs

Move some register definitions to hts221_avg_list, hts221_avg_list and
hts221_channels since they are used only there and simplify driver code

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
1 file changed