[PATCH] PCIE: make bus_id for PCI Express devices unique

The bus_id string must be unique for all devices of that bus in the
system, not just for devices with the same parent - otherwise multiple
symlinks with identical names appear in /sys/bus/pci_express/devices.

Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>