regulator (max5970): Add hwmon support

Utilize the integrated 10-bit ADC in Max5970/Max5978 to enable voltage
and current monitoring. This feature is seamlessly integrated through
the hwmon subsystem.

Signed-off-by: Naresh Solanki <naresh.solanki@9elements.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20231027152830.1269895-1-naresh.solanki@9elements.com


Signed-off-by: Mark Brown <broonie@kernel.org>