gpio: em: Fix checking return value of irq_alloc_descs

irq_alloc_descs() returns negative error code on failure.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-em.c

@@ -247,9 +247,9 @@ static int __devinit em_gio_irq_domain_init(struct em_gio_priv *p)
 
 	p->irq_base = irq_alloc_descs(pdata->irq_base, 0,
 				      pdata->number_of_pins, numa_node_id());
-	if (IS_ERR_VALUE(p->irq_base)) {
+	if (p->irq_base < 0) {
 		dev_err(&pdev->dev, "cannot get irq_desc\n");
-		return -ENXIO;
+		return p->irq_base;
 	}
 	pr_debug("gio: hw base = %d, nr = %d, sw base = %d\n",
 		 pdata->gpio_base, pdata->number_of_pins, p->irq_base);