led_class: fix typo in blink API

When I added led_blink_set I had a typo: the return value of the hw
offload is a regular error code that is zero when succesful, and in that
case software emulation should not be used, rather than the other way
around.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Cc: Richard Purdie <rpurdie@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/leds/led-class.c

@@ -267,7 +267,7 @@ void led_blink_set(struct led_classdev *led_cdev,
 		   unsigned long *delay_off)
 {
 	if (led_cdev->blink_set &&
-	    led_cdev->blink_set(led_cdev, delay_on, delay_off))
+	    !led_cdev->blink_set(led_cdev, delay_on, delay_off))
 		return;
 
 	/* blink with 1 Hz as default if nothing specified */