hwmon: (acpi_power_meter) Fix uninitialized variables

hwmon: (acpi_power_meter) Fix uninitialized variables

The 'power1_alarm' attribute uses the 'power' and 'cap' in the
acpi_power_meter_resource structure. Currently, these two fields are just
updated when user query 'power' and 'cap' attribute. If user directly query
the 'power1_alarm' attribute without queryng above two attributes, driver
will use uninitialized variables to judge.

So this patch adds the setting of alarm state and update 'cap' in the
notification callback and update 'power' and 'cap' if needed to show the
real alarm state.

Signed-off-by: Huisong Li <lihuisong@huawei.com>
Link: https://lore.kernel.org/r/20250109081708.27366-2-lihuisong@huawei.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>