mac80211: don't expose ieee80211_add_srates_ie()

This and ieee80211_add_ext_srates_ie() aren't
exported, so can't be used by drivers anyway,
but there's also no reason that they should be
so make them private to mac80211 and use sdata
instead of vif arguments.

Acked-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index ec8f5346..4e75303 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2420,9 +2420,9 @@
 		*pos++ = WLAN_EID_SSID;
 		*pos++ = 0x0;
 
-		if (ieee80211_add_srates_ie(&sdata->vif, skb, true) ||
+		if (ieee80211_add_srates_ie(sdata, skb, true) ||
 		    mesh_add_ds_params_ie(skb, sdata) ||
-		    ieee80211_add_ext_srates_ie(&sdata->vif, skb, true) ||
+		    ieee80211_add_ext_srates_ie(sdata, skb, true) ||
 		    mesh_add_rsn_ie(skb, sdata) ||
 		    mesh_add_ht_cap_ie(skb, sdata) ||
 		    mesh_add_ht_oper_ie(skb, sdata) ||