KVM: PPC: Fix typo in book3s_32 debug code

There's a typo in the debug ifdef of the book3s_32 mmu emulation. While trying
to debug something I stumbled across that and wanted to save anyone after me
(or myself later) from having to debug that again.

So let's fix the ifdef.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>