pseries: Update SLOF for NVRAM support

Now that we have implemented PAPR compatible NVRAM interfaces in qemu, this
updates the SLOF firmware to actually initialize and use the NVRAM as a
PAPR guest firmware is expected to do.

This SLOF update also includes an ugly but useful workaround for a bug in
the SLES11 installer which caused it to fail under KVM.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
