platform/x86/intel/pmc: Allow pmc_core_ssram_init to fail

platform/x86/intel/pmc: Allow pmc_core_ssram_init to fail

Currently, if the PMC SSRAM initialization fails, no error is returned and
the only indication is that a PMC device has not been created.  Instead,
allow an error to be returned and handled directly by the caller.

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/20231129222132.2331261-13-david.e.box@linux.intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>