KVM: PPC: Check max IRQ prio

We have a define on what the highest bit of IRQ priorities is. So we can
just as well use it in the bit checking code and avoid invalid IRQ values
to be triggered.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/powerpc/kvm/book3s.c

@@ -337,7 +337,7 @@ void kvmppc_core_deliver_interrupts(struct kvm_vcpu *vcpu)
 		printk(KERN_EMERG "KVM: Check pending: %lx\n", vcpu->arch.pending_exceptions);
 #endif
 	priority = __ffs(*pending);
-	while (priority <= (sizeof(unsigned int) * 8)) {
+	while (priority < BOOK3S_IRQPRIO_MAX) {
 		if (kvmppc_book3s_irqprio_deliver(vcpu, priority) &&
 		    (priority != BOOK3S_IRQPRIO_DECREMENTER)) {
 			/* DEC interrupts get cleared by mtdec */