hwmon: (pmbus/ltc2978) add support for ltm4673

Add support for LTM4673. The LTM4673 is a quad output, dual 12A and dual
5A, switching mode DC/DC step-down μModule regulator integrated with
4-channel power system manager.

This adds only the chip id, the checks for the manufacturer special id,
and the relevant attributes for the device's pmbus_driver_info.
The device does not support clear peaks.

Signed-off-by: Cedric Encarnacion <cedricjustine.encarnacion@analog.com>
Link: https://lore.kernel.org/r/20250124-ltm4673-v1-2-a2c6aa37c903@analog.com


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