platform/x86/intel/pmc/ssram: Make PMT registration optional

platform/x86/intel/pmc/ssram: Make PMT registration optional

The SSRAM telemetry driver extracts essential PMC device ID and power
management base address information that intel_pmc_core depends on for core
functionality. If PMT registration failure prevents this critical data from
being available, intel_pmc_core operation would break entirely. Therefore,
PMT registration failures must not block access to this data.

Change the behavior to log a warning when PMT registration fails but
continue with successful driver initialization, ensuring the primary
telemetry data remains accessible to dependent drivers.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Link: https://patch.msgid.link/4f4c324977951f6082bf2218c8b911e1ae7e0a7b.1781294741.git.david.e.box@linux.intel.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>