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.

In fact I changed coreDelay before deleting
the code in fidvid that called it. But there're
still a couple of calls from src/northbridge/amd/amdmct/wrappers/mcti_d.c
Since the comment encouraged fixing something, I
parametrized it with the delay time in microseconds
and paranoically tried to avoid an overflow at pathological
moments.

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@6408 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1