Adds cpufreq support for FSB changing on nForce2 platforms.  On this
plattforms the PCI/AGP clock is independent from the FSB and it also
doesn't depend on the used CPU.

From: Sebastian Witt <se.witt@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>