hwmon: (adt7470) Convert to devm_hwmon_device_register_with_info API

Use the devm_hwmon_device_register_with_info API and remove code that
deals with the standard sensor attributes.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20210826024121.15665-4-chris.packham@alliedtelesis.co.nz
[groeck: Fixed alignment issues]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>