gpiolib: Update documentation of struct acpi_gpio_info

It seems the code had been changed, but description left untouched.

Update description of the struct acpi_gpio_info and relative comments
accordingly.

Fixes: commit 52044723cd ("ACPI / gpio: Add irq_type when a GPIO is used as an interrupt")
Cc: Christophe RICARD <christophe.ricard@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib-acpi.c

@@ -416,9 +416,8 @@ static int acpi_populate_gpio_lookup(struct acpi_resource *ares, void *data)
 			agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
 
 		/*
-		 * ActiveLow is only specified for GpioInt resource. If
-		 * GpioIo is used then the only way to set the flag is
-		 * to use _DSD "gpios" property.
+		 * Polarity and triggering are only specified for GpioInt
+		 * resource.
 		 * Note: we expect here:
 		 * - ACPI_ACTIVE_LOW == GPIO_ACTIVE_LOW
 		 * - ACPI_ACTIVE_HIGH == GPIO_ACTIVE_HIGH