hwmon: (peci/dimmtemp) Do not provide fake thresholds data

commit 5797c044 upstream.

When an Icelake or Sapphire Rapids CPU isn't providing the maximum and
critical thresholds for particular DIMM the driver should return an
error to the userspace instead of giving it stale (best case) or wrong
(the structure contains all zeros after kzalloc() call) data.

The issue can be reproduced by binding the peci driver while the host is
fully booted and idle, this makes PECI interaction unreliable enough.

Fixes: 73bc1b88 ("hwmon: peci: Add dimmtemp driver")
Fixes: 621995b6 ("hwmon: (peci/dimmtemp) Add Sapphire Rapids support")
Cc: stable@vger.kernel.org
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-by: Iwona Winiarska <iwona.winiarska@intel.com>
Link: https://lore.kernel.org/r/20250123122003.6010-1-fercerpav@gmail.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>