KVM: arm: irqfd: fix value returned by kvm_irq_map_gsi

irqfd/arm curently does not support routing. kvm_irq_map_gsi is
supposed to return all the routing entries associated with the
provided gsi and return the number of those entries. We should
return 0 at this point.
Signed-off-by: NEric Auger <eric.auger@linaro.org>
Acked-by: NChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

virt/kvm/arm/vgic.c

@@ -2141,7 +2141,7 @@ int kvm_irq_map_gsi(struct kvm *kvm,
 		    struct kvm_kernel_irq_routing_entry *entries,
 		    int gsi)
 {
-	return gsi;
+	return 0;
 }
 
 int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)