mac80211: add ieee80211_sdata_running

Instead of always using netif_running(sdata->dev)
use ieee80211_sdata_running(sdata) now which is
just an inline containing netif_running() for now.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/pm.c b/net/mac80211/pm.c
index 05e161c..913dc7e 100644
--- a/net/mac80211/pm.c
+++ b/net/mac80211/pm.c
@@ -93,7 +93,7 @@
 			break;
 		}
 
-		if (!netif_running(sdata->dev))
+		if (!ieee80211_sdata_running(sdata))
 			continue;
 
 		/* disable beaconing */