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/cfg.c b/net/mac80211/cfg.c
index 63843e3..fdac1bc 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -78,17 +78,15 @@
 				  enum nl80211_iftype type, u32 *flags,
 				  struct vif_params *params)
 {
-	struct ieee80211_sub_if_data *sdata;
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	int ret;
 
-	if (netif_running(dev))
+	if (ieee80211_sdata_running(sdata))
 		return -EBUSY;
 
 	if (!nl80211_params_check(type, params))
 		return -EINVAL;
 
-	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
-
 	ret = ieee80211_if_change_type(sdata, type);
 	if (ret)
 		return ret;