dt-bindings: iio: Add KX022A accelerometer

KX022A is a 3-axis Accelerometer from ROHM/Kionix. The sensor features
include variable ODRs, I2C and SPI control, FIFO/LIFO with watermark IRQ,
tap/motion detection, wake-up & back-to-sleep events, four acceleration
ranges (2, 4, 8 and 16g) and probably some other cool features.

Add the basic device tree description for the accelerometer. Only basic
accelerometer features are considered as of now - new properties may or
may not be needed in the future when rest of the features are supported.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/06f8e1ab29d02ed216db10091a269df4b6abad9a.1666614295.git.mazziesaccount@gmail.com


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