ath9k: remove fragmentation workaround again

Looking at the RC algorithm this is no longer necessary.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath9k/main.c

@@ -2487,11 +2487,6 @@ static int ath9k_ampdu_action(struct ieee80211_hw *hw,
 	return ret;
 }
 
-static int ath9k_no_fragmentation(struct ieee80211_hw *hw, u32 value)
-{
-	return -EOPNOTSUPP;
-}
-
 static struct ieee80211_ops ath9k_ops = {
 	.tx 		    = ath9k_tx,
 	.start 		    = ath9k_start,
@@ -2508,7 +2503,6 @@ static struct ieee80211_ops ath9k_ops = {
 	.get_tsf 	    = ath9k_get_tsf,
 	.reset_tsf 	    = ath9k_reset_tsf,
 	.ampdu_action       = ath9k_ampdu_action,
-	.set_frag_threshold = ath9k_no_fragmentation,
 };
 
 static struct {