pci: pcie-altera: ipipe: enable interrupt pipelining

Fix up Altera's PCIE driver in order to channel interrupts through the
interrupt pipeline.

drivers/pci/host/pcie-altera.c

@@ -486,7 +486,7 @@ static void altera_pcie_isr(struct irq_desc *desc)
 
 			virq = irq_find_mapping(pcie->irq_domain, bit);
 			if (virq)
-				generic_handle_irq(virq);
+				ipipe_handle_demuxed_irq(virq);
 			else
 				dev_err(dev, "unexpected IRQ, INT%d\n", bit);
 		}