pinctrl: meson: fix incorrect usage of ENOSYS

ENOSYS is special and should only be used for incorrect syscall number.
It is not the case here. let's use ENOTSUPP instead.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/meson/pinctrl-meson.c

@@ -399,7 +399,7 @@ static int meson_pinconf_group_set(struct pinctrl_dev *pcdev,
 static int meson_pinconf_group_get(struct pinctrl_dev *pcdev,
 				   unsigned int group, unsigned long *config)
 {
-	return -ENOSYS;
+	return -ENOTSUPP;
 }
 
 static const struct pinconf_ops meson_pinconf_ops = {