ath10k: add directory to board data error message

This way user has a better idea what file exactly is missing.
This is needed when we switch to using request_firmware_direct() which doesn't
print any errors anymore.
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

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

@@ -1168,7 +1168,8 @@ static int ath10k_core_fetch_board_file(struct ath10k *ar)
 	ar->bd_api = 1;
 	ret = ath10k_core_fetch_board_data_api_1(ar);
 	if (ret) {
-		ath10k_err(ar, "failed to fetch board data\n");
+		ath10k_err(ar, "failed to fetch board-2.bin or board.bin from %s\n",
+			   ar->hw_params.fw.dir);
 		return ret;
 	}