powerpc/eeh: Remove eeh information from pci_dn

The patch removes the eeh information from pci_dn since the eeh
device (struct eeh_dev) already contained those information and
the copy in pci_dn is no longer used except for the pseries iommu
mapping code, which we change to retrieve the PE address from eeh
device instead.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>