iio: chemical: add driver for ENS160 sensor

ScioSense ENS160 is a digital metal oxide multi-gas sensor, designed
for indoor air quality monitoring. The driver supports readings of
CO2 and VOC, and can be accessed via both SPI and I2C.

Datasheet: https://www.sciosense.com/wp-content/uploads/2023/12/ENS160-Datasheet.pdf


Signed-off-by: Gustavo Silva <gustavograzs@gmail.com>
Link: https://lore.kernel.org/r/20240604225747.7212-4-gustavograzs@gmail.com


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