gpiolib: allow nested threaded irqs for poll(2)

The pca953x driver requires the use of threaded irqs as its irq
demultiplexer can sleep.  Our irq handler can be called from any context,
so use request_any_context_irq to allow threaded irqs as well.
Signed-off-by: NDaniel Gl?ckner <dg@emlix.com>
Reported-by: NIan Jeffray <ian@jeffray.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/gpio/gpiolib.c

@@ -386,9 +386,9 @@ static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
 		}
 	}
 
-	ret = request_irq(irq, gpio_sysfs_irq, irq_flags,
+	ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
 				"gpiolib", value_sd);
-	if (ret)
+	if (ret < 0)
 		goto free_id;
 
 	desc->flags |= gpio_flags;