PPC: mac99: Move NVRAM to page boundary when necessary

When running KVM we have to adhere to host page boundaries for memory slots.
Unfortunately the NVRAM on mac99 is a 4k RAM hole inside of an MMIO flash
area.

So if our host is configured with 64k page size, we can't use the mac99 target
with KVM. This is a real shame, as this limitation is not really an issue - we
can easily map NVRAM somewhere else and at least Linux and Mac OS X use it
at their new location.

So in that emergency case when it's about failing to run at all and moving NVRAM
to a place it shouldn't be at, choose the latter.

This patch enables -M mac99 with KVM on 64k page size hosts.

Signed-off-by: Alexander Graf <agraf@suse.de>
