gpio: sysfs: emit chardev line-state events on active-low changes

The sysfs active_low attribute doesn't go through the usual paths so it
doesn't emit the line-state event. Add the missing call to
gpiod_line_state_notify() to gpio_sysfs_set_active_low().

Reviewed-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20241031-gpio-notify-sysfs-v4-4-142021c2195c@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpiolib-sysfs.c

@@ -307,6 +307,8 @@ static int gpio_sysfs_set_active_low(struct device *dev, int value)
 		status = gpio_sysfs_request_irq(dev, flags);
 	}
 
+	gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
+
 	return status;
 }