Fix bug from r5476 re CS5536 device search during GeodeLX PCI domain enable

Fix bug from r5476 re CS5536 device search during GeodeLX PCI domain enable

cs5536.c:chipsetinit() is called during northbridge pci_domain_enable()
which happens before scan_bus() so the device tree does not have PCI
vendor/device ids yet. Let's use dev_find_slot() for now. This works
only as long as the CS5536 has PCI device id 0xf in all mainboards,
and a better solution is needed in case that ever changes!

Signed-off-by: Peter Stuge <peter@stuge.se>
Acked-by: Nathan Williams <nathan@traverse.com.au>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@5581 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1