gpio: omap: add missed spin_unlock_irqrestore in omap_gpio_irq_type

Add missed spin_unlock_irqrestore in omap_gpio_irq_type when
omap_set_gpio_triggering() is failed.

It fixes static checker warning:

	drivers/gpio/gpio-omap.c:523 omap_gpio_irq_type()
	warn: inconsistent returns 'spin_lock:&bank->lock'.

This fixes commit:
1562e4618ded ('gpio: omap: fix error handling in omap_gpio_irq_type')

Reported-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-omap.c

@@ -500,8 +500,10 @@ static int omap_gpio_irq_type(struct irq_data *d, unsigned type)
 
 	spin_lock_irqsave(&bank->lock, flags);
 	retval = omap_set_gpio_triggering(bank, offset, type);
-	if (retval)
+	if (retval) {
+		spin_unlock_irqrestore(&bank->lock, flags);
 		goto error;
+	}
 	omap_gpio_init_irq(bank, offset);
 	if (!omap_gpio_is_input(bank, offset)) {
 		spin_unlock_irqrestore(&bank->lock, flags);