xen/events: fix error code in xen_bind_pirq_msi_to_irq()

Return -ENOMEM if xen_irq_init() fails.  currently the code returns an
uninitialized variable or zero.

Fixes: 5dd9ad32 ("xen/events: drop xen_allocate_irqs_dynamic()")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Juergen Gross <jgross@ssue.com>
Link: https://lore.kernel.org/r/3b9ab040-a92e-4e35-b687-3a95890a9ace@moroto.mountainSigned-off-by: Juergen Gross <jgross@suse.com>

drivers/xen/events/events_base.c

@@ -1110,8 +1110,10 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
 
 	for (i = 0; i < nvec; i++) {
 		info = xen_irq_init(irq + i);
-		if (!info)
+		if (!info) {
+			ret = -ENOMEM;
 			goto error_irq;
+		}
 
 		irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);