gpio: pcf857x: Add IRQF_SHARED when request irq

It's quite possible that multiple pcf857x can be hooked up
to the same interrupt line with the processor. So add IRQF_SHARED
in request irq..
Signed-off-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-pcf857x.c

@@ -262,7 +262,7 @@ static int pcf857x_irq_domain_init(struct pcf857x *gpio,
 	/* enable real irq */
 	status = devm_request_threaded_irq(&client->dev, client->irq,
 				NULL, pcf857x_irq, IRQF_ONESHOT |
-				IRQF_TRIGGER_FALLING,
+				IRQF_TRIGGER_FALLING | IRQF_SHARED,
 				dev_name(&client->dev), gpio);
 
 	if (status)