linux-phytec-ti

hwmon: (core) Document new kernel API

Describe the new registration API function as well as the data
structures it requires.

Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>