Minor tweaks in the 440BX RAM init code (trivial).

Minor tweaks in the 440BX RAM init code (trivial).
Still hardcoded for Tyan S1846.

This slightly increases performance, but it's still pretty horrible.
Some RAM settings are causing a dramatically slow system (confirmed
by comparing memtest performance results of the proprietary BIOS
and our code). Haven't found the problem, yet.

Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@2717 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1