hw/ppc: Remove unused defines

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Make ppc40x CPUs available in ppcemb

Not only 44x CPUs (BookE) but also 40x CPUs can run with 1k page size.

Move the criteria to a central inline function to avoid repetition
and #ifdef'fery. Update qom-test to no longer exempt them.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
ppcemb-softmmu: Drop Mac and e500 emulation

They are still available in ppc-softmmu and ppc64-softmmu.

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