gpio: pca953x: Expand comment for "reset" GPIO in ACPI case

GPIO ACPI library is going to be stricter about resources, thus, expand
comment regarding "reset" GPIO resource in this driver to clarify its
usage in ACPI case.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-pca953x.c

@@ -777,7 +777,13 @@ static int pca953x_probe(struct i2c_client *client,
 		chip->gpio_start = -1;
 		irq_base = 0;
 
-		/* See if we need to de-assert a reset pin */
+		/*
+		 * See if we need to de-assert a reset pin.
+		 *
+		 * There is no known ACPI-enabled platforms that are
+		 * using "reset" GPIO. Otherwise any of those platform
+		 * must use _DSD method with corresponding property.
+		 */
 		reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
 						     GPIOD_OUT_LOW);
 		if (IS_ERR(reset_gpio))