gpio: xgs-iproc: fix parsing of ngpios property

of_property_read_u32 returns 0 on success, not true, so we need to
invert the check to actually take over the provided ngpio value.

Fixes: 6a41b6c ("gpio: Add xgs-iproc driver")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

Author: KanjiMonster

drivers/gpio/gpio-xgs-iproc.c

@@ -224,7 +224,7 @@ static int iproc_gpio_probe(struct platform_device *pdev)
 	}
 
 	chip->gc.label = dev_name(dev);
-	if (of_property_read_u32(dn, "ngpios", &num_gpios))
+	if (!of_property_read_u32(dn, "ngpios", &num_gpios))
 		chip->gc.ngpio = num_gpios;
 
 	irq = platform_get_irq(pdev, 0);