platform/x86: ISST: Do Not Restore SST MSRs on CPU Online Operation

platform/x86: ISST: Do Not Restore SST MSRs on CPU Online Operation

During CPU offline/online operations, the hardware retains MSR settings.
Even if all CPUs are offlined, the package does not lose its MSR
settings.

Therefore, it is unnecessary to restore MSRs which are modified during
the online operation, and this extra step can be removed.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://lore.kernel.org/r/20250505202722.1048675-1-srinivas.pandruvada@linux.intel.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>