gpiolib: add irq_not_threaded flag to gpio_chip

Some GPIO chips (e.g. the DLN2 USB adapter) have blocking get/set
operation but do not need a threaded irq handler.

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 4acf8b2..6fdae78 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -437,7 +437,7 @@
 	irq_set_lockdep_class(irq, &gpiochip_irq_lock_class);
 	irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler);
 	/* Chips that can sleep need nested thread handlers */
-	if (chip->can_sleep)
+	if (chip->can_sleep && !chip->irq_not_threaded)
 		irq_set_nested_thread(irq, 1);
 #ifdef CONFIG_ARM
 	set_irq_flags(irq, IRQF_VALID);