dt-bindings: hwmon: nuvoton,nct6775: Add compatible value for NCT6799

While NCT6799 is mostly compatible to NCT6798, it needs a separate
compatible entry because it is not completely compatible and does
require chip specific code in the driver.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Zev Weiss <zev@bewilderbeest.net>
Link: https://lore.kernel.org/r/20240221155158.2234898-1-linux@roeck-us.net


Signed-off-by: Guenter Roeck <linux@roeck-us.net>