Hi,
I think something wrong went with PCI/memory mapping. It looks somehow a hole for PCI is not created.
Try setting CONFIG_HW_MEM_HOLE_SIZEK. it should create 0-3GB ram and 1GB hole by default. Also I did not check if VIA chipset will work with memory above 4GB (in fact never owned so much memory :) maybe correct top of memory needs to be present for the chipset.
The option above will configure the memory hole which will allow the PCI devices to exists and rest of memory will be remapped above.
Again, never played with that but it might work.
Thanks Rudolf