x86: fixup numa_node information for AMD CPU northbridge functions

Currently the numa_node attribute for these PCI devices is 0 (it
corresponds to the numa_node for PCI bus 0). This is not a big issue
but incorrect.

This inconsistency can be fixed by reading the node number from CPU
NB function 0.

[ Impact: fill in dev->numa_node information, to optimize DMA allocations ]

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: jbarnes@virtuousgeek.org
LKML-Reference: <20090417100746.GG16198@alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>