Desktop Core2Duo/Core2Quad CPUs are unable to control frequency of single

Desktop Core2Duo/Core2Quad CPUs are unable to control frequency of single
CPU core, only pair of them. As result, both cores are running on highest
one of requested frequencies, and that is reported by status register.
Such behavior confuses frequency validation logic, as it runs on only
one core, as SMP is not yet launched, making EIST completely unusable.

To workaround this, add check for validation result. If we haven't found
at least two usable frequencies, then probably we are looking bad and have
to trust data provided by BIOS as-is.