JS2x: Fixed config space access functions.
JS2x: Fixed config space access functions.

According to the PCI bus binding to Open Firmware, the uppermost byte can
contain some description bits when doing "config-l@" and the like. For
accessing the config space via MMIO, we've got to mask them away.

Signed-off-by: Thomas Huth <9e65be74847981e55b2564b6266c57d86d3bac05@linux.vnet.ibm.com>

open-power-host-os/slof,agraf/SLOF,dgibson/SLOF,stefanberger/SLOF-tpm,aik/SLOF,k0da/SLOF,agraf/SLOF,agraf/SLOF,qemu/SLOF,k0da/SLOF,open-power-host-os/slof,dgibson/SLOF,k0da/SLOF,mdroth/SLOF,stefanberger/SLOF-tpm,dgibson/SLOF,aik/SLOF,leilihh/SLOF,dgibson/SLOF,qemu/SLOF,mdroth/SLOF,open-power-host-os/slof,leilihh/SLOF,k0da/SLOF,agraf/SLOF,leilihh/SLOF,leilihh/SLOF,open-power-host-os/slof,mdroth/SLOF,qemu/SLOF,mdroth/SLOF,aik/SLOF,stefanberger/SLOF-tpm