ath10k: htt: don't use txdone_fifo with SDIO

HTT High Latency (ATH10K_DEV_TYPE_HL) does not use txdone_fifo at all, we don't
even initialise it by skipping ath10k_htt_tx_alloc_buf() in
ath10k_htt_tx_start(). Because of this using QCA6174 SDIO
ath10k_htt_rx_tx_compl_ind() will crash when it accesses unitialised
txdone_fifo. So skip txdone_fifo when using High Latency mode.

Tested with QCA6174 SDIO with firmware WLAN.RMH.4.4.1-00007-QCARMSWP-1.
Co-developed-by: NWen Gong <wgong@codeaurora.org>
Signed-off-by: NAlagu Sankar <alagusankar@silex-india.com>
Signed-off-by: NWen Gong <wgong@codeaurora.org>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath10k/htt_rx.c

@@ -2277,7 +2277,9 @@ static void ath10k_htt_rx_tx_compl_ind(struct ath10k *ar,
 		 *  Note that with only one concurrent reader and one concurrent
 		 *  writer, you don't need extra locking to use these macro.
 		 */
-		if (!kfifo_put(&htt->txdone_fifo, tx_done)) {
+		if (ar->bus_param.dev_type == ATH10K_DEV_TYPE_HL) {
+			ath10k_txrx_tx_unref(htt, &tx_done);
+		} else if (!kfifo_put(&htt->txdone_fifo, tx_done)) {
 			ath10k_warn(ar, "txdone fifo overrun, msdu_id %d status %d\n",
 				    tx_done.msdu_id, tx_done.status);
 			ath10k_txrx_tx_unref(htt, &tx_done);