Otherwise when cpu_post_load calls ppc_store_sdr1() when restoring a VM
snapshot the value is deemed unchanged and so the internal env->htab*
variables aren't set correctly.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>