mac80211: check for CONFIG_MAC80211_LEDS in the tpt_led_trigger declaration

If CONFIG_MAC80211_LEDS is not set, ieee80211_i.h was failing to compile,
because struct led_trigger is only declared when CONFIG_LEDS_TRIGGERS is
set.

This patch adds ifdefs around the tpt_led_trigger declaration in
ieee80211_i.h to avoid the problem.
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/ieee80211_i.h

@@ -631,6 +631,7 @@ enum queue_stop_reason {
 	IEEE80211_QUEUE_STOP_REASON_SKB_ADD,
 };
 
+#ifdef CONFIG_MAC80211_LEDS
 struct tpt_led_trigger {
 	struct led_trigger trig;
 	char name[32];
@@ -642,6 +643,7 @@ struct tpt_led_trigger {
 	unsigned int active, want;
 	bool running;
 };
+#endif
 
 /**
  * mac80211 scan flags - currently active scan mode