pinctrl: bcm2835: Avoid warning from __irq_do_set_handler

We get a warning during boot with enabled EARLY_PRINTK that
we try to set a irq_chip without data. This is caused by ignoring
the return value of irq_of_parse_and_map(). So avoid calling
gpiochip_set_chained_irqchip() in error case.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Fixes: 85ae9e51 ("pinctrl: bcm2835: switch to GPIOLIB_IRQCHIP")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/bcm/pinctrl-bcm2835.c

@@ -1048,6 +1048,10 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 	for (i = 0; i < BCM2835_NUM_IRQS; i++) {
 		pc->irq[i] = irq_of_parse_and_map(np, i);
 		pc->irq_group[i] = i;
+
+		if (pc->irq[i] == 0)
+			continue;
+
 		/*
 		 * Use the same handler for all groups: this is necessary
 		 * since we use one gpiochip to cover all lines - the