gpio: tegra: fix unbalanced chained_irq_enter/exit

When more than one GPIO IRQs are triggered simultaneously,
tegra_gpio_irq_handler() called chained_irq_exit() multiple
times for one chained_irq_enter().

Fixes: 3c92db9ac0ca3eee8e46e2424b6c074e2e394ad9
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
[Also changed the variable to a bool]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-tegra.c

@@ -360,7 +360,7 @@ static void tegra_gpio_irq_handler(struct irq_desc *desc)
 {
 	int port;
 	int pin;
-	int unmasked = 0;
+	bool unmasked = false;
 	int gpio;
 	u32 lvl;
 	unsigned long sta;
@@ -384,8 +384,8 @@ static void tegra_gpio_irq_handler(struct irq_desc *desc)
 			 * before executing the handler so that we don't
 			 * miss edges
 			 */
-			if (lvl & (0x100 << pin)) {
-				unmasked = 1;
+			if (!unmasked && lvl & (0x100 << pin)) {
+				unmasked = true;
 				chained_irq_exit(chip, desc);
 			}