gpiolib: irq hooks: fix recursion in gpiochip_irq_unmask

irqchip shared with multiple gpiochips, leads to recursive call of
gpiochip_irq_mask/gpiochip_irq_unmask which was assigned to
rqchip->irq_mask/irqchip->irq_unmask, these happens becouse of
only irqchip->irq_enable == gpiochip_irq_enable is checked.

Let's add an additional check to make sure shared irqchip is detected
even if irqchip->irq_enable wasn't defined.

Fixes: a8173820 ("gpio: gpiolib: Allow GPIO IRQs to lazy disable")
Signed-off-by: NNikita Shubin <nikita.shubin@maquefel.me>
Link: https://lore.kernel.org/r/20201210070514.13238-1-nikita.shubin@maquefel.meSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib.c

@@ -1419,7 +1419,8 @@ static void gpiochip_set_irq_hooks(struct gpio_chip *gc)
 	if (WARN_ON(gc->irq.irq_enable))
 		return;
 	/* Check if the irqchip already has this hook... */
-	if (irqchip->irq_enable == gpiochip_irq_enable) {
+	if (irqchip->irq_enable == gpiochip_irq_enable ||
+		irqchip->irq_mask == gpiochip_irq_mask) {
 		/*
 		 * ...and if so, give a gentle warning that this is bad
 		 * practice.