ath10k: Correct error handling of dma_map_single()

[ Upstream commit d43810b2c1808ac865aa1a2a2c291644bf95345c ]

The return value of dma_map_single() should be checked for errors using
dma_mapping_error() and the skb has been dequeued so it needs to be
freed.

This was found when enabling CONFIG_DMA_API_DEBUG and it warned about the
missing dma_mapping_error() call.

Fixes: 1807da49 ("ath10k: wmi: add management tx by reference support over wmi")
Reported-by: NNiklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: NBjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

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

@@ -3844,8 +3844,10 @@ void ath10k_mgmt_over_wmi_tx_work(struct work_struct *work)
 			     ar->running_fw->fw_file.fw_features)) {
 			paddr = dma_map_single(ar->dev, skb->data,
 					       skb->len, DMA_TO_DEVICE);
-			if (!paddr)
+			if (dma_mapping_error(ar->dev, paddr)) {
+				ieee80211_free_txskb(ar->hw, skb);
 				continue;
+			}
 			ret = ath10k_wmi_mgmt_tx_send(ar, skb, paddr);
 			if (ret) {
 				ath10k_warn(ar, "failed to transmit management frame by ref via WMI: %d\n",