KVM: PPC: booke: BOOKE_IRQPRIO_MAX is n+1

The semantics of BOOKE_IRQPRIO_MAX changed to denote the highest available
irqprio + 1, so let's reflect that in the code too.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/powerpc/kvm/booke.c

@@ -425,7 +425,7 @@ static void kvmppc_core_check_exceptions(struct kvm_vcpu *vcpu)
 	}
 
 	priority = __ffs(*pending);
-	while (priority <= BOOKE_IRQPRIO_MAX) {
+	while (priority < BOOKE_IRQPRIO_MAX) {
 		if (kvmppc_booke_irqprio_deliver(vcpu, priority))
 			break;