[coreboot] [PATCH] 440BX registered SDRAM support

[Keith Hui]

See attached for patch with sign-off inside. Boot tested on ASUS
P2B-LS with both regular and registered ECC modules.

Now that I got some registered ECC modules in, I am able to code up
this patch to allow registered SDRAM to initialize. This is needed in
advance of ECC support because most ECC modules are registered. The
same modules I have also happened to be electrically "256MB single
side" so I am finally able to, unfortunately, exercise the "set it
smaller so at least I can use it" patch of r5508.

ECC is still not enabled in this patch. That would be for a separate patch.

Enjoy
Keith