hwmon: (occ) Add sysfs entry for IPS (Idle Power Saver) status

BMC control applications need to check the Idle Power Saver status
byte returned by the OCC poll response, so export it in sysfs with
the other OCC-specific data.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20220215151022.7498-2-eajames@linux.ibm.com


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