Add bindings for adp810 differential pressure and temperature
sensor. This sensor communicates over I2C with CRC support and
can measure pressure in the range -500 to 500Pa and temperature
in the range -40 to +85 degree celsius.
Signed-off-by: Akhilesh Patil <akhilesh@ee.iitb.ac.in> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>