Add documentation for the max127 hardware monitoring driver.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20201123185658.7632-3-rentao.bupt@gmail.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>