pinctrl: st: Add irq_disable hook to st_gpio_irqchip

Currently disable_irq() doesn't work for pinctrl-st driver, due to
missing irq_disable hook in the driver.
disable_irq() is required only for level-triggered interrupts, which
is not the case normally.

Signed-off-by: Pankaj Dev <pankaj.dev@st.com>
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-st.c

@@ -1445,6 +1445,7 @@ static struct gpio_chip st_gpio_template = {
 
 static struct irq_chip st_gpio_irqchip = {
 	.name		= "GPIO",
+	.irq_disable	= st_gpio_irq_mask,
 	.irq_mask	= st_gpio_irq_mask,
 	.irq_unmask	= st_gpio_irq_unmask,
 	.irq_set_type	= st_gpio_irq_set_type,