s390/pci: use claim_resource

Use pci_claim_resource to find and request bus ressources in
pcibios_add_device. Also move some (de)initialization stuff to
pcibios_enable_device/pcibios_disable_device.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>