hw/i386/kvm/ioapic: Replace magic '24' value by proper definition

Replace '24' -> KVM_IOAPIC_NUM_PINS.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/hw/i386/kvm/ioapic.c b/hw/i386/kvm/ioapic.c
index 409d0c8..b96fe84 100644
--- a/hw/i386/kvm/ioapic.c
+++ b/hw/i386/kvm/ioapic.c
@@ -35,7 +35,7 @@
         kvm_irqchip_add_irq_route(s, i, KVM_IRQCHIP_PIC_SLAVE, i - 8);
     }
     if (pci_enabled) {
-        for (i = 0; i < 24; ++i) {
+        for (i = 0; i < KVM_IOAPIC_NUM_PINS; ++i) {
             if (i == 0) {
                 kvm_irqchip_add_irq_route(s, i, KVM_IRQCHIP_IOAPIC, 2);
             } else if (i != 2) {