firenze-pci: Fix infinite loop in firenze_pci_add_loc_code()
firenze-pci: Fix infinite loop in firenze_pci_add_loc_code()

If ibm,slot-location-code isn't in a PCI device's parent node the loop
to search for it will never terminate since p = np->parent is always
going to return the same result.

Fixes: ab1b05d29f5e ("PCI: create optional loc-code platform callback")
Signed-off-by: Oliver O'Halloran <3dfaff8fa6ae977f042064a112a6aac576279b9b@gmail.com>

qemu/skiboot,legoater/skiboot,shenki/skiboot,shenki/skiboot,legoater/skiboot,legoater/skiboot,legoater/skiboot,qemu/skiboot,open-power/skiboot,shenki/skiboot,qemu/skiboot,shenki/skiboot,qemu/skiboot,open-power/skiboot,open-power/skiboot,qemu/skiboot,open-power/skiboot,legoater/skiboot,shenki/skiboot,open-power/skiboot