gpio: ep93xx: Fix typo s/hierarchial/hierarchical

Fix typo in comment.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Signed-off-by: Nikita Shubin <nikita.shubin@maquefel.me>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

drivers/gpio/gpio-ep93xx.c

@@ -388,7 +388,7 @@ static int ep93xx_gpio_add_bank(struct ep93xx_gpio_chip *egc,
 
 		/*
 		 * FIXME: convert this to use hierarchical IRQ support!
-		 * this requires fixing the root irqchip to be hierarchial.
+		 * this requires fixing the root irqchip to be hierarchical.
 		 */
 		girq->parent_handler = ep93xx_gpio_f_irq_handler;
 		girq->num_parents = 8;