Fix pattern handling optimalization

Check for zero duration before skipping step. This fixes pattern

    echo "0 1000 10 2550 0 1000" > pattern

which should do [  .-xXx-.] but does [   Xx-.]
Signed-off-by: NPavel Machek <pavel@ucw.cz>
Suggested-by: NJacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: NJacek Anaszewski <jacek.anaszewski@gmail.com>

drivers/leds/trigger/ledtrig-pattern.c

@@ -87,9 +87,10 @@ static void pattern_trig_timer_function(struct timer_list *t)
 					   data->curr->brightness);
 			mod_timer(&data->timer,
 				  jiffies + msecs_to_jiffies(data->curr->delta_t));
-
-			/* Skip the tuple with zero duration */
-			pattern_trig_update_patterns(data);
+			if (!data->next->delta_t) {
+				/* Skip the tuple with zero duration */
+				pattern_trig_update_patterns(data);
+			}
 			/* Select next tuple */
 			pattern_trig_update_patterns(data);
 		} else {