platform/x86/intel/pmt: Ignore uninitialized entries

On Intel Xeon, unused PMT regions will have uninitialized discovery headers
containing all 0xF. Instead of returning an error, just skip the region.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230413012922.1521377-1-david.e.box@linux.intel.com


Signed-off-by: Hans de Goede <hdegoede@redhat.com>