mac80211: move frame TX function

The ieee80211_sta_tx function isn't MLME code any more,
it's getting used by a lot of code. Move it to utils and
rename it to ieee80211_tx_skb.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/spectmgmt.c b/net/mac80211/spectmgmt.c
index b7129f4..f72bad6 100644
--- a/net/mac80211/spectmgmt.c
+++ b/net/mac80211/spectmgmt.c
@@ -65,7 +65,7 @@
 			IEEE80211_SPCT_MSR_RPRT_MODE_REFUSED;
 	msr_report->u.action.u.measurement.msr_elem.type = request_ie->type;
 
-	ieee80211_sta_tx(sdata, skb, 0);
+	ieee80211_tx_skb(sdata, skb, 0);
 }
 
 void ieee80211_process_measurement_req(struct ieee80211_sub_if_data *sdata,