[cns3xxx]: clean up PCI bus topology

This makes the PCI bus topology more standard for devices behind a bridge
 
Signed-off-by: Tim Harvey <tharvey@gateworks.com>


git-svn-id: svn://svn.openwrt.org/openwrt@35078 3c298f89-4303-0410-b956-a3cf2f4a3e73