ath6kl: remove redundant null pointer check on send_pkt

The check for send_pkt being NULL is redundant before the call
to htc_reclaim_txctrl_buf, therefore it should be removed. This was
detected by static analysis by cppcheck.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath6kl/htc_mbox.c

@@ -1085,9 +1085,7 @@ static int htc_setup_tx_complete(struct htc_target *target)
 	send_pkt->completion = NULL;
 	ath6kl_htc_tx_prep_pkt(send_pkt, 0, 0, 0);
 	status = ath6kl_htc_tx_issue(target, send_pkt);
-
-	if (send_pkt != NULL)
-		htc_reclaim_txctrl_buf(target, send_pkt);
+	htc_reclaim_txctrl_buf(target, send_pkt);
 
 	return status;
 }