gpio: sta2x11: Be sure to clamp return value

As we want gpio_chip .get() calls to be able to return negative
error codes and propagate to drivers, we need to go over all
drivers and make sure their return values are clamped to [0,1].
We do this by using the ret = !!(val) design pattern.

Cc: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-sta2x11.c

@@ -90,7 +90,7 @@ static int gsta_gpio_get(struct gpio_chip *gpio, unsigned nr)
 	struct gsta_regs __iomem *regs = __regs(chip, nr);
 	u32 bit = __bit(nr);
 
-	return readl(&regs->dat) & bit;
+	return !!(readl(&regs->dat) & bit);
 }
 
 static int gsta_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,