PCI hotplug: cpqphp: use pci_dev->vendor

The driver reads PCI vendor ID from the PCI configuration register while it is
already stored by the PCI subsystem in the 'vendor' field of 'struct pci_dev'...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>