qemu-softmmu-ppc64 is supposed to be a superset of qemu-softmmu-ppc.
However, instead of simply including the 32-bit config file, we've
duplicated all CONFIG_xxx settings there instead. This way, we've missed
some CONFIG switches in ppc64-softmmu.mak which were only added to the
32-bit config file (e.g. CONFIG_SUNGEM). Let's fix this problem by
including the 32-bit config file into the 64-bit config file instead
of duplicating all the CONFIG switches there.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>