PCI: xilinx: Fix xilinx_pcie_assign_msi() return value test

We should be testing "hwirq" instead of "irq".  "irq" is unsigned so it's
never less than zero.  Also it's uninitialized.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NSrikanth Thokala <sthokal@xilinx.com>

drivers/pci/host/pcie-xilinx.c

@@ -359,8 +359,8 @@ static int xilinx_pcie_msi_setup_irq(struct msi_chip *chip,
 	phys_addr_t msg_addr;
 
 	hwirq = xilinx_pcie_assign_msi(port);
-	if (irq < 0)
-		return irq;
+	if (hwirq < 0)
+		return hwirq;
 
 	irq = irq_create_mapping(port->irq_domain, hwirq);
 	if (!irq)