hwmon: (nct6775) Documentation updates

Document support for NCT6102D/NCT6104D/NCT6106D and NCT6791D.
Document that NCT5573D is compatible to NCT6775F with the same chip ID.

Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>