KVM: PPC: Fix debug macros

When XICS_DBG is enabled, gcc produces format errors. This fixes
formats to match passed values types.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>