hwmon: (pmbus/ltc2978) add support for lt717x

hwmon: (pmbus/ltc2978) add support for lt717x

Add support for LT7170 and LT7171. The LT7170 and LT7171 are 20 A, 16 V,
Single- or Dual-Phase, Silent Switcher Step-Down Regulators with Digital
Power System Management.

The relevant registers in the LT7170 and LT7171 are similar to those in
the LTC3887, but with fewer channels. This adds the chip ID and
identification of ASCII to differentiate between the LT7170 and LT7171.
These devices support polling for status updates and clearing peak
values. The data format for voltage, current, and temperature is set to
IEEE754 for precision and compatibility.

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>
Link: https://lore.kernel.org/r/20250317-hwmon-next-v1-3-da0218c38197@analog.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>