dt-bindings: hwmon: ltc2978: add support for LT717x

Add LTC7170 and LT7171 to supported devices of LTC2978. It has similar
set of registers to LTC3887, differing only in number of channels and
some PMBUS status and functionalities.

Co-developed-by: Cherrence Sarip <cherrence.sarip@analog.com>
Signed-off-by: Cherrence Sarip <cherrence.sarip@analog.com>
Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250317-hwmon-next-v1-2-da0218c38197@analog.com


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