mfd: rtsx_usb: Add comment in rtsx_usb_suspend

Explain why there is no need to have a symmetric LED turn-on in resume handler
while calling rtsx_usb_turn_off_led() in suspend handler.
Signed-off-by: Roger Tseng <rogerable@realtek.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/rtsx_usb.c

@@ -687,9 +687,15 @@ static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
 	dev_dbg(&intf->dev, "%s called with pm message 0x%04u\n",
 			__func__, message.event);
 
+	/*
+	 * Call to make sure LED is off during suspend to save more power.
+	 * It is NOT a permanent state and could be turned on anytime later.
+	 * Thus no need to call turn_on when resunming.
+	 */
 	mutex_lock(&ucr->dev_mutex);
 	rtsx_usb_turn_off_led(ucr);
 	mutex_unlock(&ucr->dev_mutex);
+
 	return 0;
 }