gpio: regmap: Use -ENOTSUPP consistently

The GPIO library expects the drivers to return -ENOTSUPP in some cases
and not using analogue POSIX code. Make the driver to follow this.
Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpio-regmap.c

@@ -129,7 +129,7 @@ static int gpio_regmap_get_direction(struct gpio_chip *chip,
 		base = gpio_regmap_addr(gpio->reg_dir_in_base);
 		invert = 1;
 	} else {
-		return -EOPNOTSUPP;
+		return -ENOTSUPP;
 	}
 
 	ret = gpio->reg_mask_xlate(gpio, base, offset, &reg, &mask);
@@ -160,7 +160,7 @@ static int gpio_regmap_set_direction(struct gpio_chip *chip,
 		base = gpio_regmap_addr(gpio->reg_dir_in_base);
 		invert = 1;
 	} else {
-		return -EOPNOTSUPP;
+		return -ENOTSUPP;
 	}
 
 	ret = gpio->reg_mask_xlate(gpio, base, offset, &reg, &mask);