mac80211: tx: delete a redundant if statement in ieee80211_check_fast_xmit()

If statement is meaningless because the code will goto out regardless of
whether fast_tx is NULL or not.
Signed-off-by: NHangyu Hua <hbh25y@gmail.com>
Link: https://lore.kernel.org/r/20220413091902.27438-1-hbh25y@gmail.comSigned-off-by: NJohannes Berg <johannes.berg@intel.com>

net/mac80211/tx.c

@@ -3150,8 +3150,6 @@ void ieee80211_check_fast_xmit(struct sta_info *sta)
 
 	fast_tx = kmemdup(&build, sizeof(build), GFP_ATOMIC);
 	/* if the kmemdup fails, continue w/o fast_tx */
-	if (!fast_tx)
-		goto out;
 
  out:
 	/* we might have raced against another call to this function */