PCI: dwc: Use private data pointer of "struct irq_domain" to get pcie_port

No functional change. Get "struct pcie_port *" from private data
pointer of "struct irq_domain" in dw_pcie_irq_domain_free() to make
it look similar to how "struct pcie_port *" is obtained in
dw_pcie_irq_domain_alloc()

Link: https://lore.kernel.org/r/20191220100550.777-1-kishon@ti.comSigned-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -236,7 +236,7 @@ static void dw_pcie_irq_domain_free(struct irq_domain *domain,
 				    unsigned int virq, unsigned int nr_irqs)
 {
 	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
-	struct pcie_port *pp = irq_data_get_irq_chip_data(d);
+	struct pcie_port *pp = domain->host_data;
 	unsigned long flags;
 
 	raw_spin_lock_irqsave(&pp->lock, flags);