gpio: mxs: read pin level directly instead of using .get

Calling readl directly instead of going through another function that
results in the same result to remove some overhead. I didn't try to
measure the performance gain, but IMHO there is little benefit from
abstracting a GPIO register access in the GPIO driver.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-mxs.c

@@ -84,7 +84,7 @@ static int mxs_gpio_set_irq_type(struct irq_data *d, unsigned int type)
 	port->both_edges &= ~pin_mask;
 	switch (type) {
 	case IRQ_TYPE_EDGE_BOTH:
-		val = port->gc.get(&port->gc, d->hwirq);
+		val = readl(port->base + PINCTRL_DIN(port)) & pin_mask;
 		if (val)
 			edge = GPIO_INT_FALL_EDGE;
 		else