First part of heterogenous dualchannel support.

First part of heterogenous dualchannel support.

Do not allow non-identical DIMMs yet, but prepare the code.

Calculate tCL related settings per DIMM in a dual channel setup. The
check for compatibility will come in a later patch, but since DIMMs
still have to be identical, this does not hurt.

Factor out tRC calculation to prepare for per-DIMM calculation.

Add diagnostic messages to tRC code.

Test booted to FILO, behaviour is identical if you ignore the added
debug messages (which are switched off by default).

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@3867 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1