gpiolib: keep comment consistent with code

The commit f881bab0 ("gpio: keep the GPIO line names internal")
change the error to warning in gpiochip_set_desc_names. Update the
comment accordingly.
Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib.c

@@ -252,7 +252,7 @@ static struct gpio_desc *gpio_name_to_desc(const char * const name)
  * Takes the names from gc->names and checks if they are all unique. If they
  * are, they are assigned to their gpio descriptors.
  *
- * Returns -EEXIST if one of the names is already used for a different GPIO.
+ * Warning if one of the names is already used for a different GPIO.
  */
 static int gpiochip_set_desc_names(struct gpio_chip *gc)
 {