device/pci: Replace use of dev_find_slot() for IRQs

Change-Id: I48c0de73338430282ce1a4442bbeb7c867dc174c
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34079
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/arch/x86/pirq_routing.c

@@ -177,7 +177,7 @@ static void pirq_route_irqs(unsigned long addr)
 		}
 
 		/* Bus, device, slots IRQs for {A,B,C,D}. */
-		pci_assign_irqs(bus, devfn >> 3, irq_slot);
+		pci_assign_irqs(pcidev_path_on_bus(bus, devfn), irq_slot);
 	}
 
 	for (i = 0; i < CONFIG_MAX_PIRQ_LINKS; i++)