gpio-ml-ioh: fix error return code in ioh_gpio_probe()

Fix to return a negative error code in the irq descs alloc error
handling case instead of 0, as done elsewhere in this function.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-ml-ioh.c

@@ -465,6 +465,7 @@ static int ioh_gpio_probe(struct pci_dev *pdev,
 			dev_warn(&pdev->dev,
 				"ml_ioh_gpio: Failed to get IRQ base num\n");
 			chip->irq_base = -1;
+			ret = irq_base;
 			goto err_irq_alloc_descs;
 		}
 		chip->irq_base = irq_base;