Refactor K8 rev F DDR2 CL timing retrieval.

Refactor K8 rev F DDR2 CL timing retrieval.
This will allow usage of compatible DIMMS in a dual channel setup
instead of requiring the DIMMS to be identical.

Code impact is minimal because a large chunk of code has been moved into
a separate function with almost no changes.

Tested, yields identical results and identical logs.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Peter Stuge <peter@stuge.se>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3866 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1