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/sta_info.c b/net/mac80211/sta_info.c
index d1a77e7..f039e76 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -367,7 +367,7 @@
 	 * something inserts a STA (on one CPU) without holding the RTNL
 	 * and another CPU turns off the net device.
 	 */
-	if (unlikely(!netif_running(sdata->dev))) {
+	if (unlikely(!ieee80211_sdata_running(sdata))) {
 		err = -ENETDOWN;
 		goto out_free;
 	}