wireless: fix a few sparse warnings

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index c643e37..2b3b490 100644
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -225,7 +225,7 @@
 	return sample_ndx;
 }
 
-void
+static void
 minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
 		  void *priv_sta, struct ieee80211_tx_rate_control *txrc)
 {