Change Geode GX2 to use the auto DRAM detect code from Geode LX.

Change Geode GX2 to use the auto DRAM detect code from Geode LX.

Also, change the GX2 boards to use it.

Add a processor speed setting function in human readable MHz and remove
the useless and broken PLLMSR settings (the processor speed was hardcoded
to 366MHz in pll_reset.c).

Signed-off-by: Nils Jacobs <njacobs8@hetnet.nl>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6011 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1