Improving BKDG implementation of P-states,

Improving BKDG implementation of P-states,
CPU and northbridge frequency and voltage
handling for Fam 10 in SVI mode.

Well, I understand it better like this, but maybe
it's only me, part of the changes are paranoic, and
the only effective change is for a factor depending on
mobile or not that I can't test.

Signed-off-by: Xavi Drudis Ferran <xdrudis@tinet.cat>
Acked-by: Marc Jones <marcj303@gmail.com>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6406 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1