hwmon: (pmbus/core) Add regulator event support

Add regulator events corresponding to regulator error in regulator flag
map.
Also capture the same in pmbus_regulator_get_flags.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Link: https://lore.kernel.org/r/20230328150335.90238-2-Naresh.Solanki@9elements.com


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