[CPUFREQ] Support different families in fid/did to frequency conversion

The equation to find the frequency given the fid and did is family dependant.

Acked-by: Mark Langsdorf <mark.langsdorf@amd.com>
Signed-off-by: Joachim Deguara <joachim.deguara@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>